0001110805-21-000009 | 10-K | XBRL Viewer

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DEI Document - USD ($) $ in Billions	12 Months Ended
DEI Document - USD ($) $ in Billions	Dec. 31, 2020	Jan. 31, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-16417
Entity Registrant Name	NUSTAR ENERGY L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	74-2956831
Entity Address, Address Line One	19003 IH-10 West
Entity Address, City or Town	San Antonio
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78257
City Area Code	(210)
Local Phone Number	918-2000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1.4
Entity Partnership Units Outstanding		109,468,140
Entity Central Index Key	0001110805
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Limited Partner [Member]
Document Information [Line Items]
Title of 12(b) Security	Common units
Trading Symbol	NS
Security Exchange Name	NYSE
Series A Preferred Limited Partner [Member]
Document Information [Line Items]
Title of 12(b) Security	Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units
Trading Symbol	NSprA
Security Exchange Name	NYSE
Series B Preferred Limited Partner [Member]
Document Information [Line Items]
Title of 12(b) Security	Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units
Trading Symbol	NSprB
Security Exchange Name	NYSE
Series C Preferred Limited Partner [Member]
Document Information [Line Items]
Title of 12(b) Security	Series C Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units
Trading Symbol	NSprC
Security Exchange Name	NYSE

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 153,625	$ 16,192
Accounts receivable, net	133,473	152,530
Inventories	11,059	12,393
Prepaid and other current assets	25,400	21,933
Total current assets	323,557	203,048
Property, plant and equipment, at cost	6,164,742	6,187,144
Accumulated depreciation and amortization	(2,207,230)	(2,068,165)
Property, plant and equipment, net	3,957,512	4,118,979
Intangible assets, net	630,209	681,632
Goodwill	766,416	1,005,853
Other long-term assets, net	139,324	176,480
Total assets	5,817,018	6,185,992
Current liabilities:
Accounts payable	71,731	109,834
Current portion of debt and finance lease obligations	3,839	462,413
Accrued interest payable	50,847	37,925
Accrued liabilities	77,770	108,610
Taxes other than income tax	16,998	12,781
Total current liabilities	221,185	731,563
Long-term debt, less current portion	3,593,496	2,934,918
Deferred income tax liability	13,011	12,427
Other long-term liabilities	157,825	148,939
Total liabilities	3,985,517	3,827,847
Commitments and contingencies (Note 15)
Series D preferred limited partners (23,246,650 units outstanding as of  December 31, 2020 and 2019) (Note 18)	599,542	581,935
Partners’ equity (Note 19):
Common limited partners (109,468,127 and 108,527,806 common units outstanding as of December 31, 2020 and 2019, respectively)	572,314	1,087,805
Accumulated other comprehensive loss	(96,656)	(67,896)
Total partners' equity	1,231,959	1,776,210
Liabilities and Equity, Total	5,817,018	6,185,992
Series A Preferred Limited Partner [Member]
Partners’ equity (Note 19):
Preferred limited partners	218,307	218,307
Series B Preferred Limited Partner [Member]
Partners’ equity (Note 19):
Preferred limited partners	371,476	371,476
Series C Preferred Limited Partner [Member]
Partners’ equity (Note 19):
Preferred limited partners	$ 166,518	$ 166,518

CONSOLIDATED BALANCE SHEETS (parenthetical) - shares	Dec. 31, 2020	Dec. 31, 2019
Series D preferred units outstanding	23,246,650	23,246,650
Limited partners common units outstanding	109,468,127	108,527,806
Series A Preferred Limited Partner [Member]
Preferred units outstanding	9,060,000	9,060,000
Series B Preferred Limited Partner [Member]
Preferred units outstanding	15,400,000	15,400,000
Series C Preferred Limited Partner [Member]
Preferred units outstanding	6,900,000	6,900,000

CONSOLIDATED STATEMENTS OF (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Total revenues	$ 1,481,564	$ 1,498,021	$ 1,520,262
Costs and expenses:
Goodwill impairment loss	225,000	0	0
General and administrative expenses (excluding depreciation and amortization expense)	102,716	107,855	100,067
Other depreciation and amortization expense	8,625	8,360	8,604
Total costs and expenses	1,272,462	1,107,105	1,184,534
Operating income	209,102	390,916	335,728
Interest expense, net	(229,054)	(183,070)	(184,398)
Loss on extinguishment of debt	(141,746)	0	0
Other (expense) income, net	(34,622)	3,742	5,202
Income (loss) from continuing operations before income tax expense (benefit)	(196,320)	211,588	156,532
Income tax expense	2,663	4,754	10,157
Income (loss) from continuing operations, net of tax	(198,983)	206,834	146,375
Income (loss) from discontinued operations, net of tax	0	(312,527)	59,419
Net income (loss)	$ (198,983)	$ (105,693)	$ 205,794
Basic net income (loss) per common unit (Note 20)
Continuing operations	$ (3.15)	$ 0.60	$ (3.34)
Discontinued operations	0	(2.90)	0.57
Total net income (loss) per common unit	(3.15)	(2.30)	(2.77)
Diluted net income (loss) per common unit (Note 20)
Continuing operations	(3.15)	0.60	(3.34)
Discontinued operations	0	(2.90)	0.57
Total net income (loss) per common unit	$ (3.15)	$ (2.30)	$ (2.77)
Basic weighted-average common units outstanding	109,155,117	107,789,030	99,490,495
Diluted weighted-average common units outstanding	109,155,117	107,854,699	99,531,172
Service [Member]
Revenues:
Total revenues	$ 1,205,494	$ 1,148,167	$ 1,045,130
Costs and expenses:
Operating expenses (excluding depreciation and amortization expense)	403,579	404,682	378,962
Depreciation and amortization expense	276,476	264,564	247,288
Total costs associated with service revenues/Cost associated with product sales	680,055	669,246	626,250
Product [Member]
Revenues:
Total revenues	276,070	349,854	475,132
Costs and expenses:
Total costs associated with service revenues/Cost associated with product sales	$ 256,066	$ 321,644	$ 449,613

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income (loss)	$ (198,983)	$ (105,693)	$ 205,794
Other comprehensive income (loss):
Foreign currency translation adjustment	1,410	3,527	4,304
Net (loss) gain on pension and other postretirement benefit adjustments, net of income tax benefit (expense) of $28, $14 and ($94)	(4,144)	(1,314)	2,334
Net (loss) gain on cash flow hedges	(26,026)	(15,231)	23,411
Total other comprehensive income (loss)	(28,760)	(13,018)	30,049
Comprehensive income (loss)	$ (227,743)	$ (118,711)	$ 235,843

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Income tax (expense) benefit	$ 28	$ 14	$ (94)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income (loss)	$ (198,983)	$ (105,693)	$ 205,794
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization expense	285,101	281,460	297,874
Amortization of unit-based compensation	11,477	14,386	12,004
Amortization of debt related items	11,463	5,209	7,388
Loss from sale or disposition of assets	38,084	3,499	41,272
Gain from insurance recoveries	0	0	(78,756)
Asset and goodwill impairment losses	225,000	336,838	0
Loss on extinguishment of debt	141,746	0	0
Deferred income tax expense (benefit)	212	(476)	2,043
Changes in current assets and current liabilities (Note 21)	11,928	(44,765)	78,262
(Increase) decrease in other long-term assets	(8,101)	22,020	(3,029)
Increase (decrease) in other long-term liabilities	7,920	(1,407)	(17,832)
Other, net	151	(2,314)	(813)
Net cash provided by operating activities	525,998	508,757	544,207
Cash Flows from Investing Activities:
Capital expenditures	(198,079)	(533,568)	(457,452)
Change in accounts payable related to capital expenditures	(10,645)	(12,731)	(7,683)
Acquisition	0	0	(37,502)
Proceeds from insurance recoveries	0	0	78,419
Proceeds from sale or disposition of assets	110,640	228,152	270,440
Other, net	0	(1,100)	0
Net cash (used in) provided by investing activities	(98,084)	(319,247)	(153,778)
Cash Flows from Financing Activities:
Proceeds from Term Loan, net of discount and issuance costs	463,045	0	0
Proceeds from note offerings, net of issuance costs	1,182,035	491,580	0
Proceeds from other long-term debt borrowings	883,748	659,300	1,254,153
Proceeds from short-term debt borrowings	52,000	307,500	618,500
Term Loan repayment, including debt extinguishment costs	(601,316)	0	0
Other long-term debt repayments	(1,813,963)	(928,900)	(1,746,776)
Short-term debt repayments	(57,500)	(320,500)	(635,000)
Proceeds from issuance of Series D preferred units	0	0	590,000
Payment of issuance costs for Series D preferred units	0	0	(34,203)
Proceeds from issuance of common units, including contributions from general partner	0	15,000	10,204
Distributions to preferred unitholders	(124,622)	(121,693)	(90,670)
Distributions to common unitholders and general partner	(196,203)	(258,354)	(300,777)
Cash consideration for Merger (Note 5)	0	0	(67,795)
Proceeds from (payments for) termination of interest rate swaps	(49,225)	0	8,048
Payment of tax withholding for unit-based compensation	(10,028)	(8,771)	(2,083)
(Decrease) increase in cash book overdrafts	(2,288)	(3,752)	2,935
Other, net	(17,067)	(9,060)	(6,403)
Net cash provided by (used in) financing activities	(291,384)	(177,650)	(399,867)
Effect of foreign exchange rate changes on cash	916	(524)	(1,210)
Net increase (decrease) in cash, cash equivalents and restricted cash	137,446	11,336	(10,648)
Cash, cash equivalents and restricted cash as of the beginning of the period	24,980	13,644	24,292
Cash, cash equivalents and restricted cash as of the end of the period	$ 162,426	$ 24,980	$ 13,644

CONSOLIDATED STATEMENTS OF PARTNERS' EQUITY AND MEZZANINE EQUITY - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive Loss [Member]	Preferred Limited Partner [Member]	Common Limited Partner [Member]	General Partner [Member]	General Partner and Common Limited Partners [Member]	Series D Preferred Limited Partner [Member]
Partners' capital - beginning balance at Dec. 31, 2017	$ 2,480,089	$ (84,927)	$ 756,603	$ 1,770,587	$ 37,826
Temporary equity - beginning balance at Dec. 31, 2017	0
Partners' capital and temporary equity - beginning balance at Dec. 31, 2017	2,480,089
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	205,794	0	64,091	110,788	2,466
Net income (loss), excluding portion attributable to temporary equity	177,345
Net income, temporary equity							$ 28,449
Other comprehensive income (loss)	30,049	30,049	0	0	0
Cash distributions to partners			(64,091)	(286,398)	(14,379)	$ (300,777)
Distributions to partners, temporary equity							(28,449)
Issuance of units, including contribution from general partner	10,204	0		10,000	204
Issuance of Series D preferred units							555,797
Unit-based compensation	7,925	0	0	7,925	0
Adjustments related to the Merger (refer to Note 5 for discussion)	(67,972)	0	0	(41,973)	(25,999)
Series D Preferred Unit accretion, common	(8,195)			(8,195)
Series D Preferred Unit accretion, preferred							8,195
Series D Preferred Unit accretion, total	0
Other	(6,846)	0	(302)	(6,426)	(118)
Other, temporary equity							0
Other, including temporary equity	(6,846)
Partners' capital - ending balance at Dec. 31, 2018	2,257,731	(54,878)	756,301	1,556,308	0
Temporary equity - ending balance at Dec. 31, 2018	563,992
Partners' capital and temporary equity - ending balance at Dec. 31, 2018	2,821,723
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(105,693)	0	64,134	(227,386)	0
Net income (loss), excluding portion attributable to temporary equity	(163,252)
Net income, temporary equity							57,559
Other comprehensive income (loss)	(13,018)	(13,018)	0	0	0
Cash distributions to partners			(64,134)	(258,354)
Distributions to partners, temporary equity							(57,559)
Issuance of units, including contribution from general partner	15,000	0		15,000	0
Unit-based compensation	20,766	0	0	20,766	0
Series D Preferred Unit accretion, common	(18,085)			(18,085)
Series D Preferred Unit accretion, preferred							18,085
Series D Preferred Unit accretion, total	0
Other	(444)	0	0	(444)	0
Other, temporary equity							(142)
Other, including temporary equity	(586)
Partners' capital - ending balance at Dec. 31, 2019	1,776,210	(67,896)	756,301	1,087,805	0
Temporary equity - ending balance at Dec. 31, 2019	581,935
Partners' capital and temporary equity - ending balance at Dec. 31, 2019	2,358,145
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(198,983)	0	64,134	(323,865)	0
Net income (loss), excluding portion attributable to temporary equity	(259,731)
Net income, temporary equity							60,748
Other comprehensive income (loss)	(28,760)	(28,760)	0	0	0
Cash distributions to partners			(64,134)	(196,203)
Distributions to partners, temporary equity							(60,748)
Unit-based compensation	22,219	0	0	22,219	0
Series D Preferred Unit accretion, common	(17,626)			(17,626)
Series D Preferred Unit accretion, preferred							17,626
Series D Preferred Unit accretion, total	0
Other	(16)	0	0	(16)	0
Other, temporary equity							$ (19)
Other, including temporary equity	(35)
Partners' capital - ending balance at Dec. 31, 2020	1,231,959	$ (96,656)	$ 756,301	$ 572,314	$ 0
Temporary equity - ending balance at Dec. 31, 2020	599,542
Partners' capital and temporary equity - ending balance at Dec. 31, 2020	$ 1,831,501

CONSOLIDATED STATEMENTS OF PARTNERS' EQUITY AND MEZZANINE EQUITY (parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Limited Partner [Member]
Cash distributions paid, per unit	$ 1.80	$ 2.40	$ 2.895

ORGANIZATION AND OPERATIONS	12 Months Ended
ORGANIZATION AND OPERATIONS	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND OPERATIONS	ORGANIZATION AND OPERATIONS Organization NuStar Energy L.P. (NYSE: NS) is engaged in the transportation of petroleum products and anhydrous ammonia, and the terminalling, storage and marketing of petroleum products. Unless otherwise indicated, the terms “NuStar Energy,” “NS,” “the Partnership,” “we,” “our” and “us” are used in this report to refer to NuStar Energy L.P., to one or more of our consolidated subsidiaries or to all of them taken as a whole. Our business is managed under the direction of the board of directors of NuStar GP, LLC, the general partner of our general partner, Riverwalk Logistics, L.P., both of which are wholly owned subsidiaries of NuStar GP Holdings, LLC (Holdings), which became a wholly owned subsidiary of ours on July 20, 2018. Recent Developments COVID-19 and OPEC+ Actions. The coronavirus, or COVID-19, has had a severe negative impact on global economic activity, as government authorities instituted stay-home orders, business closures and other measures to reduce the spread of the virus, and people around the world ceased or altered their usual day-to-day activities. The scale of this decrease in economic activity has significantly reduced demand for petroleum products. In March 2020, the negative economic impact of the COVID-19 pandemic and demand deterioration was exacerbated by disputes among the Organization of Petroleum Exporting Countries and other oil-producing nations (OPEC+) regarding their agreed production rates that contributed to a significant over-supply in crude oil, resulting in a sharp decline in, and increase in the volatility of, crude oil prices. Beginning with the second quarter of 2020, crude oil prices stabilized somewhat, and although lower compared to recent years, crude oil prices began to increase in the fourth quarter of 2020. In March 2020, the negative impact of the COVID-19 pandemic, combined with actions by OPEC+, also drove significant declines in stock prices and market capitalization of companies across the energy industry, including NuStar’s. As a result, we recorded a goodwill impairment charge of $225.0 million associated with our crude oil pipelines in the first quarter of 2020. Please refer to Note 11 for additional information. Although the continuing impact of the COVID-19 pandemic and actions by OPEC+ have depressed global economic activity, which has had a negative impact on our results of operations, particularly during the second quarter of 2020, we began to see some initial signs of recovery and rebound in June, which improved our results of operations for the remainder of 2020. Ongoing uncertainty surrounding the COVID-19 pandemic, including its duration and lingering impacts to the economy, as well as uncertainty surrounding future production decisions by OPEC+, continue to cause volatility and could have a significant impact on management’s estimates and assumptions in 2021 and beyond. Sale of Texas City Terminals. On December 7, 2020, we sold the equity interests in our wholly owned subsidiaries that owned two terminals in Texas City, Texas for $106.0 million, subject to adjustment. We recorded a non-cash loss of $34.7 million and utilized the sales proceeds to improve our debt metrics. Please refer to Note 4 for further discussion. Senior Notes. On September 14, 2020, NuStar Logistics issued $600.0 million of 5.75% senior notes due October 1, 2025 and $600.0 million of 6.375% senior notes due October 1, 2030. We received proceeds of $1,182.0 million, net of issuance costs of $18.0 million, which we used to repay outstanding borrowings under the Term Loan, as defined below, as well as outstanding borrowings under our revolving credit agreement. On September 1, 2020, we repaid our $450.0 million of 4.80% senior notes at maturity with borrowings under our revolving credit agreement. Please refer to Note 13 for further discussion. Term Loan Credit Agreement. On April 19, 2020, NuStar Energy and NuStar Logistics entered into an unsecured term loan credit agreement with certain lenders and Oaktree Fund Administration, LLC, as administrative agent for the lenders (the Term Loan). The Term Loan provided for an aggregate commitment of up to $750.0 million pursuant to a three-year unsecured term loan credit facility. On April 21, 2020 we drew $500.0 million, which we repaid on September 16, 2020. The repayment required certain contractual premiums, and we recognized a loss of $137.9 million in the third quarter of 2020. On February 16, 2021, we terminated the Term Loan. Please refer to Note 13 for further discussion about the Term Loan. Other Events Selby Terminal Fire. On October 15, 2019, our terminal facility in Selby, California experienced a fire that destroyed two storage tanks and temporarily shut down the terminal. The property damage was isolated, and in the fourth quarter of 2019, we incurred losses of $5.4 million, which represent the aggregate amount of our deductibles under various insurance policies. For the year ended December 31, 2020, we received insurance proceeds of $35.0 million, of which $6.7 million was for business interruption and is included in “Operating expenses” in the consolidated statement of loss. Insurance proceeds relate to cleanup costs and business interruption and are therefore included in “Cash flows from operating activities” in the consolidated statement of cash flows. In addition, we received $20.5 million of insurance proceeds in January and February of 2021. We believe we have adequate insurance to offset additional costs. Sale of St. Eustatius and European Operations. On July 29, 2019, we sold our St. Eustatius terminal and bunkering operations (the St. Eustatius Operations) for net proceeds of approximately $230.0 million (the St. Eustatius Disposition). In 2019, we recorded long-lived asset and goodwill impairment charges totaling $336.8 million related to the St. Eustatius Operations in “(Loss) income from discontinued operations, net of tax” on our consolidated statement of loss. In the second quarter of 2019, we determined the St. Eustatius Operations and the European operations, as discussed below, met the requirements to be reported as discontinued operations, and as a result, we reclassified certain balances to assets and liabilities held for sale and certain revenues and expenses to discontinued operations for all applicable periods presented. On November 30, 2018, we sold our European operations for approximately $270.0 million (the European Disposition). The operations sold included six liquids storage terminals in the United Kingdom and one facility in Amsterdam with total storage capacity of approximately 9.5 million barrels (the European Operations). We recognized a non-cash loss of $43.4 million related to the sale in “(Loss) income from discontinued operations, net of tax” on our consolidated statement of income for the year ended December 31, 2018. Please refer to Note 4 for further discussion. Merger. On July 20, 2018, we completed the merger of Holdings with a subsidiary of NS. Under the terms of the merger agreement, Holdings unitholders received 0.55 of a common unit representing a limited partner interest in NS in exchange for each Holdings unit owned at the effective time of the merger. Please refer to Note 5 for further discussion of the merger. Hurricane Activity. In the third quarter of 2017, several of our facilities were affected by the hurricanes in the Caribbean and Gulf of Mexico, including the St. Eustatius terminal, which experienced the most damage and was temporarily shut down. In 2018, we received the remaining insurance proceeds of $87.5 million in settlement of our property damage claim for the St. Eustatius terminal, of which $9.1 million related to business interruption. Proceeds from business interruption insurance are included in “Cash flows from operating activities” in the consolidated statements of cash flows. We recorded a $78.8 million gain in the consolidated statement of income in 2018 for the amount by which the insurance proceeds exceeded our expenses incurred during the period. The insurance proceeds related to business interruption and the gain are included in “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income. Operations We conduct our operations through our subsidiaries, primarily NuStar Logistics, L.P. (NuStar Logistics) and NuStar Pipeline Operating Partnership L.P. (NuPOP). We have three business segments: pipeline, storage and fuels marketing. Pipeline. We own 3,205 miles of refined product pipelines and 2,205 miles of crude oil pipelines, as well as 5.6 million barrels of crude oil storage capacity, which comprise our Central West System. In addition, we own 2,500 miles of refined product pipelines, consisting of the East and North Pipelines, and a 2,000-mile ammonia pipeline, which comprise our Central East System. The East and North Pipelines have storage capacity of 7.4 million barrels. We charge tariffs on a per barrel basis for transporting refined products, crude oil and other feedstocks in our refined product and crude oil pipelines and on a per ton basis for transporting anhydrous ammonia in the Ammonia Pipeline. Storage. We own terminal and storage facilities in the United States, Canada and Mexico, with 59.0 million barrels of storage capacity. Our terminal and storage facilities provide storage, handling and other services on a fee basis for petroleum products, crude oil, specialty chemicals and other liquids. Fuels Marketing. The fuels marketing segment includes our bunkering operations in the Gulf Coast, as well as certain of our blending operations associated with our Central East System.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Dec. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Consolidation The accompanying consolidated financial statements represent the consolidated operations of the Partnership and our subsidiaries. Inter-partnership balances and transactions have been eliminated in consolidation. The operations of certain pipelines and terminals in which we own an undivided interest are proportionately consolidated in the accompanying consolidated financial statements. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. On an ongoing basis, management reviews its estimates based on currently available information. Management may revise estimates due to changes in facts and circumstances. Cash and Cash Equivalents Cash equivalents are all highly liquid investments with an original maturity of three months or less when acquired. Accounts Receivable On January 1, 2020, we adopted new guidance from the Financial Accounting Standards Board (FASB) on credit losses, as discussed in Note 3. Trade receivables are carried at amortized cost, net of a valuation allowance for current expected credit losses. We extend credit to certain customers after review of various credit indicators, including the customer’s credit rating, and obtain letters of credit, guarantees or collateral as deemed necessary. We monitor our ongoing credit exposure through active review of customer balances against contract terms and due dates and pool customer receivables based upon days outstanding, which is our primary credit risk indicator. Our review activities include timely account reconciliations, dispute resolution and payment confirmations. Prior to adoption of the new guidance, outstanding customer receivable balances were regularly reviewed for possible non-payment indicators and allowances for doubtful accounts were recorded based upon management’s estimate of collectability at the time of its review. Inventories Inventories consist of petroleum products, materials and supplies. Inventories are valued at the lower of cost or net realizable value. Cost is determined using the weighted-average cost method. Our inventory, other than materials and supplies, consists of one end-product category, petroleum products, which we include in the fuels marketing segment. Accordingly, we determine lower of cost or net realizable value adjustments on an aggregate basis. Materials and supplies are valued at the lower of average cost or net realizable value. Restricted Cash As of December 31, 2020 and 2019, we have restricted cash representing legally restricted funds that are unavailable for general use totaling $8.8 million, which is included in “Other long-term assets, net” on the consolidated balance sheet. Property, Plant and Equipment We record additions to property, plant and equipment, including reliability and strategic capital expenditures, at cost. Repair and maintenance costs associated with existing assets that are minor in nature and do not extend the useful life of existing assets are charged to operating expenses as incurred. Depreciation of property, plant and equipment is recorded on a straight-line basis over the estimated useful lives of the related assets. When property or equipment is retired, sold or otherwise disposed of, the difference between the carrying value and the net proceeds is recognized in “Other (expense) income, net” or “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income in the year of disposition. We capitalize overhead costs and interest costs incurred on funds used to construct property, plant and equipment while the asset is under construction. The overhead costs and capitalized interest are recorded as part of the asset to which they relate and are amortized over the asset’s estimated useful life as a component of depreciation expense. Goodwill We assess goodwill for impairment annually on October 1, or more frequently if events or changes in circumstances indicate it might be impaired. We have the option to first assess qualitative factors to determine whether it is necessary to perform a quantitative goodwill impairment test. We elected to bypass the qualitative assessment for all reporting units as of October 1, 2020 and performed a quantitative assessment. We performed a qualitative assessment as of October 1, 2019 and determined that goodwill was not impaired. We adopted amended accounting guidance in the first quarter of 2019 to measure goodwill impairment as the excess of each reporting unit’s carrying value over its fair value, not to exceed the carrying amount of goodwill for that reporting unit. The carrying value of each reporting unit equals the total identified assets (including goodwill) less the sum of each reporting unit’s identified liabilities. We used reasonable and supportable methods to assign the assets and liabilities to the appropriate reporting units in a consistent manner. As of December 31, 2020 and 2019, our reporting units to which goodwill has been allocated consisted of the following: •crude oil pipelines; •refined product pipelines; and •terminals, excluding our Point Tupper facility and our refinery crude storage tanks. As discussed in Note 11, in the first quarter of 2020, we recognized a goodwill impairment charge of $225.0 million associated with the crude oil pipelines reporting unit. In the first quarter of 2019, we recognized a goodwill impairment charge of $31.1 million for the goodwill associated with the Statia Bunkering reporting unit, which consisted of our bunkering operations at the St. Eustatius terminal facility. We recognize an impairment of goodwill if the carrying value of a reporting unit that contains goodwill exceeds its estimated fair value. In order to estimate the fair value of the reporting unit, including goodwill, management must make certain estimates and assumptions that affect the total fair value of the reporting unit including, among other things, an assessment of market conditions, projected cash flows, discount rates and growth rates. Management’s estimates of projected cash flows related to the reporting unit include, but are not limited to, future earnings of the reporting unit, assumptions about the use or disposition of the asset, estimated remaining life of the asset, and future expenditures necessary to maintain the asset’s existing service potential. We calculate the estimated fair value of each of our reporting units using a weighted-average of values calculated using an income approach and a market approach. The income approach involves estimating the fair value of each reporting unit by discounting its estimated future cash flows using a discount rate that would be consistent with a market participant’s assumption. The market approach bases the fair value measurement on information obtained from observed stock prices of public companies and recent merger and acquisition transaction data of comparable entities. Although we determined that no impairment charges resulted from our October 1, 2020 impairment assessment, the fair value of the crude oil pipelines reporting unit, which is included in the pipeline reporting segment, exceeded its carrying value by approximately 4%. The goodwill associated with the crude oil pipelines reporting unit totaled $308.6 million as of December 31, 2020. Our estimate of the fair value of the crude oil pipelines reporting unit is sensitive to typical valuation assumptions, particularly our estimates for the weighted-average cost of capital (WACC) used for the income approach and the guideline public company (GPC) multiple used for the market approach. Considering that the carrying value of the reporting unit was written down to its fair value with the first quarter of 2020 impairment charge, as further discussed in Note 11, changes to the WACC or GPC multiple used in our estimate could cause the fair value to be less than the carrying value of the crude oil pipelines reporting unit, resulting in an impairment. The fair values of the refined product pipelines and terminals reporting units substantially exceed their carrying values. Management’s estimates are based on numerous assumptions about future operations and market conditions, which we believe to be reasonable but are inherently uncertain. The uncertainties underlying our assumptions and estimates could differ significantly from actual results, including with respect to the duration and severity of the COVID-19 pandemic, the extent of travel restrictions, business closures and other efforts to control the spread of COVID-19 and the impact of actions by OPEC+, which could lead to a different determination of the fair value of our assets. We will continue to monitor the business and consider additional interim analysis of goodwill as appropriate. Impairment of Long-Lived Assets We review long-lived assets, including property, plant and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. We evaluate recoverability using undiscounted estimated net cash flows generated by the related asset or asset group. If the results of that evaluation indicate that the undiscounted cash flows are less than the carrying amount of the asset (i.e., the asset is not recoverable) we perform an impairment analysis. If our intent is to hold the asset for continued use, we determine the amount of impairment as the amount by which the net carrying value exceeds its fair value. If our intent is to sell the asset, and the criteria required to classify an asset as held for sale are met, we determine the amount of impairment as the amount by which the net carrying amount exceeds its fair value less costs to sell. As discussed in Note 4, we recognized long-lived asset impairment charges of $305.7 million in 2019 related to the St. Eustatius terminal facility. We believe that the carrying amounts of our long-lived assets as of December 31, 2020 are recoverable. Income Taxes We are a limited partnership and generally are not subject to federal or state income taxes. Accordingly, our taxable income or loss, which may vary substantially from income or loss reported for financial reporting purposes, is generally included in the federal and state income tax returns of our partners. For transfers of publicly held common units subsequent to our initial public offering, we have made an election permitted by Section 754 of the Internal Revenue Code (the Code) to adjust the common unit purchaser’s tax basis in our underlying assets to reflect the purchase price of the units. This results in an allocation of taxable income and expenses to the purchaser of the common units, including depreciation deductions and gains and losses on sales of assets, based upon the new unitholder’s purchase price for the common units. We conduct certain of our operations through taxable wholly owned corporate subsidiaries. We account for income taxes related to our taxable subsidiaries using the asset and liability method. Under this method, we recognize deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. We measure deferred taxes using enacted tax rates expected to apply to taxable income in the year those temporary differences are expected to be recovered or settled. We recognize a tax position if it is more likely than not that the tax position will be sustained, based on the technical merits of the position, upon examination. We record uncertain tax positions in the financial statements at the largest amount of benefit that is more likely than not to be realized. We had no unrecognized tax benefits as of December 31, 2020 and 2019. NuStar Energy and certain of its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. For U.S. federal and state purposes, as well as for our major non-U.S. jurisdictions, tax years subject to examination are 2016 through 2019, according to standard statute of limitations. Asset Retirement Obligations We record a liability for asset retirement obligations at the fair value of the estimated costs to retire a tangible long-lived asset at the time we incur that liability, which is generally when the asset is purchased, constructed or leased, when we have a legal obligation to incur costs to retire the asset and when a reasonable estimate of the fair value of the obligation can be made. If a reasonable estimate cannot be made at the time the liability is incurred, we record the liability when sufficient information is available to estimate the fair value. We have asset retirement obligations with respect to certain of our assets due to various legal obligations to clean and/or dispose of those assets at the time they are retired. However, these assets can be used for an extended and indeterminate period of time as long as they are properly maintained and/or upgraded. It is our practice and current intent to maintain our assets and continue making improvements to those assets based on technological advances. As a result, we believe that our assets have indeterminate lives for purposes of estimating asset retirement obligations because dates or ranges of dates upon which we would retire these assets cannot reasonably be estimated at this time. When a date or range of dates can reasonably be estimated for the retirement of any asset, we estimate the costs of performing the retirement activities and record a liability for the fair value of these costs. We also have legal obligations in the form of leases and right-of-way agreements, which require us to remove certain of our assets upon termination of the agreement. However, these lease or right-of-way agreements generally contain automatic renewal provisions that extend our rights indefinitely or we have other legal means available to extend our rights. Liabilities for conditional asset retirement obligations related to the retirement of terminal assets with lease and right-of-way agreements were not material as of December 31, 2020 and 2019. Environmental Remediation Costs Environmental remediation costs are expensed and an associated accrual established when site restoration and environmental remediation and cleanup obligations are either known or considered probable and can be reasonably estimated. These environmental obligations are based on estimates of probable undiscounted future costs using currently available technology and applying current regulations, as well as our own internal environmental policies. The environmental liabilities have not been reduced by possible recoveries from third parties. Environmental costs include initial site surveys, costs for remediation and restoration and ongoing monitoring costs, as well as fines, damages and other costs, when applicable and estimable. Adjustments to initial estimates are recorded, from time to time, to reflect changing circumstances and estimates based upon additional information developed in subsequent periods. Revenue Recognition Revenue-Generating Activities. Revenues for the pipeline segment are derived from interstate and intrastate pipeline transportation of refined products, crude oil and anhydrous ammonia and the applicable pipeline tariff. Revenues for the storage segment include fees for tank storage agreements, whereby a customer agrees to pay for a certain amount of storage in a tank over a period of time (storage terminal revenues), and throughput agreements, whereby a customer pays a fee per barrel for volumes moving through our terminals (throughput terminal revenues). Our terminals also provide blending, additive injections, handling and filtering services for which we charge additional fees, and certain of our facilities charge fees to provide marine services such as pilotage, tug assistance, line handling, launch service, emergency response services and other ship services (all of which are considered optional services). Revenues for the fuels marketing segment are derived from the sale of petroleum products. Within our pipeline and storage segments, we provide services on uninterruptible and interruptible bases. Uninterruptible services within our pipeline segment typically result from contracts that contain take-or-pay minimum volume commitments (MVCs) from the customer. Contracts with MVCs obligate the customer to pay for that minimum amount. If a customer fails to meet its MVC for the applicable service period, the customer is obligated to pay a deficiency fee based upon the shortfall between the actual volumes transported or stored and the MVC for that service period (deficiency payments). In exchange, those contracts with MVCs obligate us to stand ready to transport volumes up to the customer’s MVC. Within our storage segment, uninterruptible services arise from contracts containing a fixed monthly fee for the portion of storage capacity reserved by the customer. These contracts require that the customer pay the fixed monthly fee, regardless of whether or not it uses our storage facility (i.e., take-or-pay obligation), and that we stand ready to store that volume. Interruptible services within our pipeline and storage segments are generally provided when and to the extent we determine the requested capacity is available. The customer typically pays a per-unit rate for the actual quantities of services it receives. For the majority of our contracts, we recognize revenue in the amount to which we have a right to invoice. Generally, payment terms do not exceed 30 days. Performance Obligations. The majority of our contracts contain a single performance obligation. For our pipeline segment, the single performance obligation encompasses multiple activities necessary to deliver our customers’ products to their destinations. Typically, we satisfy this performance obligation over time as the product volume is delivered in or out of the pipelines. Certain of our pipeline segment customer contracts include an incentive pricing structure, which provides a discounted rate for the remainder of the contract once the customer exceeds a cumulative volume. The ability to receive discounted future services represents a material right to the customer, which results in a second performance obligation in those contracts. The performance obligation for our storage segment consists of multiple activities necessary to receive, store and deliver our customers’ products. We typically satisfy this performance obligation over time as the product volume is delivered in or out of the tanks (for throughput terminal revenues) or with the passage of time (for storage terminal revenues). Product sales contracts associated with our fuels marketing segment generally include a single performance obligation to deliver specified volumes of a commodity, which we satisfy at a point in time, when the product is delivered and the customer obtains control of the commodity. Optional services described in our contracts do not provide a material right to the customer, and are not considered a separate performance obligation in the contract. If and when a customer elects an optional service, and the terms of the contract are otherwise met, those services become part of the existing performance obligation. Transaction Price. For uninterruptible services, we determine the transaction price at contract inception based on the guaranteed minimum amount of revenue over the term of the contract. For interruptible services and optional services, we determine the transaction price based on our right to invoice the customer for the value of services provided to the customer for the applicable period. In certain instances, our customers reimburse us for capital projects, in arrangements referred to as contributions in aid of construction, or CIAC. Typically, in these instances, we receive upfront payments for future services, which are included in the transaction price of the underlying service contract. We collect taxes on certain revenue transactions to be remitted to governmental authorities, which may include sales, use, value-added and some excise taxes. These taxes are not included in the transaction price and are, therefore, excluded from revenues. Allocation of Transaction Price. We allocate the transaction price to the single performance obligation that exists in the vast majority of our contracts with customers. For the few contracts that have a second performance obligation, such as those that include an incentive pricing structure, we calculate an average rate based on the estimated total volumes to be delivered over the term of the contract and the resulting estimated total revenue to be billed using the applicable rates in the contract. We allocate the transaction price to the two performance obligations by applying the average rate to product volumes as they are delivered to the customer over the term of the contract. Determining the timing and amount of volumes subject to these incentive pricing contracts requires judgment that can impact the amount of revenue allocated to the two separate performance obligations. We base our estimates on our analysis of expected future production information available from our customers or other sources, which we update at least quarterly. Some of our MVC contracts include provisions that allow the customer to apply deficiency payments to future service periods (the carryforward period). In those instances, we have not satisfied our performance obligation as we still have the obligation to perform those services, subject to contractual and/or capacity constraints, at the customer’s request. At least quarterly, we assess the customer’s ability to utilize any deficiency payments during the carryforward period. If we receive a deficiency payment from a customer that we expect the customer to utilize during the carryforward period, we defer that amount as a contract liability. We will consider the performance obligation satisfied and allocate any deferred deficiency payments to our performance obligation when the customer utilizes the deficiency payment, the carryforward period ends or we determine the customer cannot or will not utilize the deficiency payment (i.e. breakage). If our contract does not allow the customer to apply deficiency payments to future service periods, we allocate the deficiency payment to the already satisfied portion of the performance obligation. Income Allocation Our partnership agreement contains provisions for the allocation of net income to the unitholders and, prior to the merger with our general partner, to the general partner. Our net income for each quarterly reporting period is first allocated to the preferred limited partner unitholders in an amount equal to the earned distributions for the respective reporting period and, prior to the merger, then to the general partner in an amount equal to the general partner’s incentive distribution calculated based upon the declared distribution for the respective reporting period. We allocate the remaining net income or loss among the common unitholders. Prior to the merger, we allocated the remaining net income or loss among the common unitholders (98%) and general partner (2%). See Note 5 for further discussion of the merger. Basic and Diluted Net (Loss) Income Per Common Unit Basic and diluted net (loss) income per common unit are determined pursuant to the two-class method. Under this method, all earnings are allocated to our limited partners and participating securities based on their respective rights to receive distributions earned during the period. Participating securities include restricted units awarded under our long-term incentive plans and, prior to the merger with our general partner, included our general partner’s interest. We compute basic net (loss) income per common unit by dividing net (loss) income attributable to our common limited partners by the weighted-average number of common units outstanding during the period. We compute diluted net (loss) income per common unit by dividing net (loss) income attributable to our common limited partners by the sum of (i) the weighted-average number of common units outstanding during the period and (ii) the effect of dilutive potential common units outstanding during the period. Dilutive potential common units include contingently issuable performance units awarded and the Series D Preferred Units. See Note 23 for additional information on our performance units, Note 18 for additional information on our Series D Preferred Units and Note 20 for the calculation of basic and diluted net (loss) income per common unit. Derivative Financial Instruments When we apply hedge accounting, we formally document all relationships between hedging instruments and hedged items. This process includes identification of the hedging instrument and the hedged transaction, the nature of the risk being hedged and how the hedging instrument’s effectiveness will be assessed. To qualify for hedge accounting, at inception of the hedge we assess whether the derivative instruments that are used in our hedging transactions are expected to be highly effective in offsetting changes in cash flows. Throughout the designated hedge period and at least quarterly, we assess whether the derivative instruments are highly effective and continue to qualify for hedge accounting. We enter into the forward-starting swaps in order to hedge the risk of changes in the interest payments attributable to changes in the benchmark interest rate during the period from the effective date of the swap to the issuance of the forecasted debt. For forward-starting interest rate swaps designated and qualifying as cash flow hedges, we recognize the fair value of each interest rate swap in the consolidated balance sheets. We record changes in the fair value of the hedge as a component of accumulated other comprehensive income (loss) (AOCI), to the extent those cash flow hedges remain highly effective. If at any point a cash flow hedge ceases to qualify for hedge accounting, changes in the fair value of the hedge are recognized in “Interest expense, net” from that date forward. The amount accumulated in AOCI is amortized into “Interest expense, net” as the forecasted interest payments occur or if the interest payments are probable not to occur. We classify cash flows associated with our derivative instruments as operating cash flows in the consolidated statements of cash flows, except for receipts or payments associated with terminated forward-starting interest rate swap agreements, which are included in cash flows from financing activities. See Note 17 for additional information regarding our derivative financial instruments. Unit-based Compensation Unit-based compensation for our long-term incentive plans is recorded in our consolidated balance sheets based on the fair value of the awards granted and recognized as compensation expense primarily on a straight-line basis over the requisite service period. Forfeitures of our unit-based compensation awards are recognized as an adjustment to compensation expense when they occur. Unit-based compensation expense is included in “General and administrative expenses” on our consolidated statements of (loss) income. Most of our currently outstanding awards are classified as equity awards as we intend to settle these awards through the issuance of our common units. See Note 23 for additional information regarding our unit-based compensation. Foreign Currency Translation The functional currencies of our foreign subsidiaries are the local currencies of the countries in which the subsidiaries are located. The assets and liabilities of our foreign subsidiaries with local functional currencies are translated to U.S. dollars at period-end exchange rates, and income and expense items are translated to U.S. dollars at weighted-average exchange rates in effect during the period. These translation adjustments are included in “Accumulated other comprehensive loss” in the equity section of the consolidated balance sheets. Gains and losses on foreign currency transactions are included in “Other (expense) income, net” or “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income. Reclassifications We have reclassified certain previously reported amounts in the consolidated financial statements and notes to conform to current-period presentation.

NEW ACCOUNTING PRONOUNCEMENTS	12 Months Ended
NEW ACCOUNTING PRONOUNCEMENTS	Dec. 31, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS Management’s Discussion and Analysis, Selected Financial Data, and Supplementary Financial Information In November 2020, the Securities and Exchange Commission (SEC) issued final rules to modernize, simplify, and enhance certain financial disclosure requirements in Regulation S-K. Among other changes, the amended guidance eliminates the requirements to present five-year selected financial data and the two-year quarterly financial data table in the Annual Report on Form 10-K. The rule changes became effective on February 10, 2021, and we are required to apply the amended rules in our filings for the fiscal year ending on December 31, 2021. Early application by amended Regulation S-K item is permitted any time after the effective date. We elected to apply provisions related to selected financial data and quarterly financial information in our Annual Report on Form 10-K for the year ended December 31, 2020 and expect to apply the remaining provisions in our Annual Report on Form 10-K for the year ended December 31, 2021. Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity In August 2020, the FASB issued guidance intended to simplify the accounting for convertible instruments by eliminating certain accounting models for convertible debt instruments and convertible preferred stock. In addition, the guidance amends the derivatives scope exception for contracts in an entity’s own equity, the disclosure requirements for convertible instruments, and certain earnings-per-unit guidance. The guidance is effective for annual periods beginning after December 15, 2021, and early adoption is permitted for annual periods beginning after December 15, 2020. Amendments may be applied using either a modified retrospective approach or a fully retrospective approach. We plan to adopt the amended guidance on January 1, 2022 and are currently assessing the impact of this amended guidance on our financial position, results of operations and disclosures. We plan to provide additional information about the expected impact at a future date. Reference Rate Reform In March 2020, the FASB issued guidance intended to provide relief to companies impacted by reference rate reform. The amended guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. Our variable-rate debt instruments use LIBOR as a benchmark for establishing the interest rate. In addition, the distribution rates on our Series A, B and C preferred units convert from fixed rates to floating rates based on LIBOR, beginning in December 2021, June 2022 and December 2022, respectively. The U.K. Financial Conduct Authority has announced its expectation that the publication of U.S. dollar LIBOR rates for the most common tenors will cease after publication on June 30, 2023, instead of on December 31, 2021 as previously expected. The FASB’s guidance is effective as of March 12, 2020 through December 31, 2022. We adopted the guidance on the effective date on a prospective basis. The guidance did not have an impact on our financial position, results of operations or disclosures at transition, but we will continue to evaluate its impact on contracts and hedging relationships modified on or before December 31, 2022. Financial Disclosures about Guarantors and Issuers of Guaranteed Securities In March 2020, the SEC issued final rules regarding presentation of financial information for issuer and guarantor entities. The final rules reduce the number of periods for which issuer and guarantor financial information is required and allow presentation of summarized financial information in lieu of separate financial statements, either in Management’s Discussion and Analysis or in the Notes to the Financial Statements in the periodic reports on Form 10-K and Form 10-Q. The guidance is effective for fiscal periods ending after January 4, 2021, with early adoption permitted. We elected to early adopt the guidance and began presenting financial information related to our issuer and guarantor entities in accordance with the final rules in the “Liquidity and Capital Resources” section of Items 1., 2. and 7. “Business, Properties and Management’s Discussion and Analysis of Financial Condition and Results of Operations” of this report. The adoption resulted in a reduction of our guarantor financial statement disclosures but did not impact our financial condition or results of operations. Simplifying the Accounting for Income Taxes In December 2019, the FASB issued amended guidance that simplifies the accounting for income taxes, including enacted changes in tax laws in interim periods. The guidance is effective for annual and interim periods beginning after December 15, 2020, with early adoption permitted. These provisions should be applied retrospectively, prospectively, or on a modified retrospective basis depending on the area affected by the amended guidance. We adopted the amended guidance on January 1, 2021, and the guidance did not have a material impact on our financial position, results of operations or disclosures. Cloud Computing Arrangements In August 2018, the FASB issued guidance addressing a customer’s accounting for implementation costs incurred in a cloud computing arrangement (CCA) that is considered a service contract. The new guidance specifies that an entity would apply the capitalization criteria for implementation costs related to internal-use software to determine which implementation costs related to a CCA that is a service contract should be capitalized and which should be expensed. The amendments also require that capitalized implementation costs be classified in the same balance sheet line item as prepayments related to the CCA and, generally, amortized on a straight-line basis over the term of the CCA. Amortization of capitalized implementation costs should be presented in the same income statement line item as CCA service fees, and cash flows for capitalized implementation costs should be presented consistently with those related to the CCA service. The guidance is effective for annual and interim periods beginning after December 15, 2019, with early adoption permitted. Prospective adoption for eligible costs incurred on or after the date of adoption or retrospective adoption is permitted. We adopted the guidance on January 1, 2020 on a prospective basis, and the guidance did not have a material impact on our financial position, results of operations or disclosures. Disclosures for Defined Benefit Plans In August 2018, the FASB issued amended guidance that makes minor changes to the disclosure requirements for employers that sponsor defined benefit pension and/or other postretirement benefit plans. The guidance is effective for annual periods ending after December 15, 2020, with early adoption permitted, using a retrospective approach. We adopted the amended guidance for the year ended December 31, 2020, and the guidance did not have a material impact on our disclosures. Credit Losses In June 2016, the FASB issued amended guidance that requires the use of a “current expected loss” model for financial assets measured at amortized cost and certain off-balance sheet credit exposures. Under this model, entities will be required to estimate the lifetime expected credit losses on such instruments based on historical experience, current conditions, and reasonable and supportable forecasts. This amended guidance also expands the disclosure requirements to enable users of financial statements to understand an entity’s assumptions, models and methods for estimating expected credit losses. The changes are effective for annual and interim periods beginning after December 15, 2019, and amendments should be applied using a modified retrospective approach. We adopted the amended guidance on January 1, 2020, and the amended guidance did not have a material impact on our financial position, results of operations or disclosures.

DISPOSITIONS AND DISCONTINUED OPERATIONS

12 Months Ended

Dec. 31, 2020

Discontinued Operations and Disposal Groups [Abstract]

DISPOSITIONS AND DISCONTINUED OPERATIONS

Sale of Texas City Terminals

On December 7, 2020, we sold the equity interests in our wholly owned subsidiaries that owned two terminals in Texas City, Texas for $106.0 million, subject to adjustment (the Texas City Sale). The two terminals have an aggregate storage capacity of 3.0 million barrels and were previously included in our storage segment. We recorded a non-cash loss of $34.7 million in “Other (expense) income, net” on our consolidated statement of loss for the year ended December 31, 2020 and utilized the sales proceeds to improve our debt metrics.

Sale of St. Eustatius Operations

Impairments. On January 28, 2019, the U.S. Department of the Treasury’s Office of Foreign Assets Control added Petroleos de Venezuela, S.A. (PDVSA), at the time a customer at the St. Eustatius facility, to its List of Specially Designated Nationals and Blocked Persons (the SDN List). The inclusion of PDVSA on the SDN List required us to wind down our contracts with PDVSA. Prior to winding down such contracts, PDVSA was the St. Eustatius terminal’s largest customer. The effect of the sanctions issued against PDVSA, combined with the progression in the sale negotiations that occurred during March 2019, resulted in triggering events that caused us to evaluate the long-lived assets and goodwill associated with the St. Eustatius terminal and bunkering operations for potential impairment.

With respect to the terminal operations long-lived assets, our estimates of future expected cash flows included the possibility of a near-term sale, as well as continuing to operate the terminal. The carrying value of the terminal’s long-lived assets exceeded our estimate of the total expected cash flows, indicating the long-lived assets were potentially impaired. To determine an impairment amount, we estimated the fair value of the long-lived assets for comparison to the carrying amount of those assets. Our estimate of the fair value considered the expected sales price as well as estimates generated from income and market approaches using a market participant’s assumptions. The estimated fair values resulting from the market and income approaches were consistent with the expected sales price. Therefore, we concluded that the estimated sales price, which was less than the carrying amount of the long-lived assets, represented the best estimate of fair value at March 31, 2019, and we recorded a long-lived asset impairment charge of $297.3 million in the first quarter of 2019 to reduce the carrying value of the assets to their estimated fair value. We recorded an additional impairment charge of $8.4 million in the second quarter of 2019, mainly due to additional capital expenditures incurred in the second quarter.

With respect to the goodwill in the Statia Bunkering reporting unit, which consisted of our bunkering operations at the St. Eustatius terminal facility, we estimated the fair value based on the expected sales price discussed above, which is inclusive of the bunkering operations. As a result, we concluded the goodwill was impaired. Consistent with FASB’s amended goodwill impairment guidance discussed in Note 2, which we adopted in the first quarter of 2019, we measured the goodwill impairment as the difference between the reporting unit’s carrying value and its fair value. Therefore, we recognized a goodwill impairment charge of $31.1 million in the first quarter of 2019 to reduce the goodwill to $0 for the Statia Bunkering reporting unit.

The impairment charges are included in “(Loss) income from discontinued operations, net of tax” on the consolidated statement of loss.

Discontinued Operations. During the second quarter of 2019, we determined the assets and liabilities associated with the St. Eustatius Operations met the criteria to be classified as held for sale. We determined the St. Eustatius Operations and the European Operations, discussed below, met the requirements to be reported as discontinued operations since the St. Eustatius Disposition and the European Disposition together represented a strategic shift that will have a major impact on our operations and financial results. These sales were part of our plan to improve our debt metrics and partially fund capital projects to grow our core business in North America. Accordingly, the consolidated balance sheet reflects the assets and liabilities associated with the St. Eustatius Operations as held for sale as of December 31, 2018, and the consolidated statements of (loss) income reflect the St. Eustatius Operations and the European Operations as discontinued operations for all applicable periods presented.

On July 29, 2019, we sold the St. Eustatius Operations for net proceeds of approximately $230.0 million. The St. Eustatius Disposition included a 14.3 million barrel storage and terminalling facility and related assets on the island of St. Eustatius in the Caribbean Netherlands. We previously reported the terminal operations in our storage segment and the bunkering operations in our fuels marketing segment. We recognized a non-cash loss on the sale of $3.9 million in “(Loss) income from discontinued operations, net of tax” on the consolidated statement of loss in 2019.

On November 30, 2018, we sold our European Operations for approximately $270.0 million. The European Operations were previously reported in our storage segment. In association with the European Disposition, we recognized a non-cash loss of $43.4 million in “(Loss) income from discontinued operations, net of tax” on the consolidated statement of income for the year ended December 31, 2018.

The following is a reconciliation of the major classes of line items included in “(Loss) income from discontinued operations, net of tax” on the consolidated statements of (loss) income:


	Year Ended December 31,
	2019		2018
	(Thousands of Dollars)



Revenues	$	248,981	$	441,495
Costs and expenses:





Cost of revenues	220,595		407,256
Impairment losses	336,838		—
General and administrative expenses (excluding depreciation and amortization expense)	1,231		6,133
Other depreciation and amortization expense	—		271
Total costs and expenses	558,664		413,660
Operating (loss) income	(309,683)		27,835
Interest income (expense), net	32		(1,839)
Other (expense) income, net	(2,775)		34,674
(Loss) income from discontinued operations before income tax expense	(312,426)		60,670
Income tax expense	101		1,251
(Loss) income from discontinued operations, net of tax	$	(312,527)	$	59,419

The consolidated statements of cash flows have not been adjusted to separately disclose cash flows related to discontinued operations. The following table presents selected cash flow information associated with our discontinued operations:


	Year Ended December 31,
	2019		2018
	(Thousands of Dollars)
Capital expenditures	$	(27,954)	$	(114,811)

Significant noncash operating activities and other adjustments:
Depreciation and amortization expense	$	8,536	$	41,982
Asset impairment losses	$	305,715	$	—
Goodwill impairment loss	$	31,123	$	—
Loss from sale of the St. Eustatius Operations	$	3,942	$	—
Loss from sale of the European Operations	$	—	$	43,366
Gain from insurance recoveries	$	—	$	(78,756)

MERGER AND RELATED PARTY AGREEMENTS

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

MERGER AND RELATED PARTY TRANSACTIONS

MERGER AND RELATED PARTY AGREEMENTS

On July 20, 2018, we completed the merger of Holdings with a subsidiary of NuStar Energy (the Merger). Pursuant to the Merger agreement and at the effective time of the Merger, NuStar Energy’s partnership agreement was amended and restated to, among other things, (i) cancel the incentive distribution rights held by our general partner, (ii) convert the 2% general partner interest in NuStar Energy held by our general partner into a non-economic management interest and (iii) provide the holders of our common units with voting rights in the election of the members of the board of directors of NuStar GP, LLC, beginning at the annual meeting in 2019.

At the effective time of the Merger, each outstanding Holdings common unit was converted into the right to receive 0.55 of a NuStar Energy common unit and all Holdings common units ceased to be outstanding. As a result of the Merger, we issued

approximately 23.6 million NuStar Energy common units and cancelled the 10.2 million NuStar Energy common units owned by subsidiaries of Holdings, resulting in approximately 13.4 million incremental NuStar Energy common units outstanding after the Merger. In addition, we repaid Holdings’ debt with borrowings under our revolving credit agreement and incurred transaction costs for aggregate cash consideration of approximately $68.0 million.

Also at the effective time of the Merger, each outstanding award of Holdings restricted units was converted, on the same terms and conditions as were applicable to the awards immediately prior to the Merger, into an award of NuStar Energy restricted units. The number of NuStar Energy restricted units subject to the converted awards was determined pursuant to the 0.55 exchange ratio provided in the Merger Agreement.

Following the completion of the Merger, the NuStar GP, LLC board of directors consists of nine members, currently composed of the six members of the NuStar GP, LLC board of directors prior to the Merger and the three independent directors who served prior to the Merger on Holdings’ board of directors.

We accounted for the Merger as an equity transaction similar to a redemption or induced conversion of preferred stock. The excess of (x) the fair value of the consideration transferred in exchange for the outstanding Holdings units over (y) the carrying value of the general partner interest in the Partnership was subtracted from net income available to common unitholders in the calculation of net loss per common unit attributable to the Merger as follows (in thousands of dollars, except unit and per unit data):


Consideration transferred:
Fair value of incremental NS common units issued	$	335,106
Holdings debt and assumed net current liabilities	52,075
Transaction costs	15,897
Total consideration	403,078

Carrying value of general partner interest	25,999
Loss to common unitholders attributable to the Merger	$	(377,079)

For the year ended December 31, 2018:
Basic weighted-average common units outstanding	99,490,495
Loss per common unit attributable to the Merger	$	(3.79)

Related Party Agreements with Holdings

GP Services Agreement. Prior to the Merger, we were a party to an Amended and Restated Services Agreement with NuStar GP, LLC, effective March 1, 2016 (the Amended GP Services Agreement), which provided that we furnish administrative services necessary to conduct the business of Holdings, and Holdings compensated us for these services for an annual fee of $1.0 million, subject to adjustment based on the annual merit increase percentage applicable to our employees for the most recently completed fiscal year and for changes in level of service. We terminated the Amended GP Services Agreement in conjunction with the Merger.

Non-Compete Agreement. Prior to the Merger, we were a party to a non-compete agreement with Holdings, Riverwalk Logistics, L.P. and NuStar GP, LLC, effective on December 22, 2006 (the Non-Compete Agreement). Under the Non-Compete Agreement, we had the right of first refusal with respect to the potential acquisition of assets related to the transportation, storage or terminalling of crude oil, feedstocks or refined products (including petrochemicals) in the United States and internationally. Holdings had a right of first refusal with respect to the potential acquisition of general partner and other equity interests in publicly traded partnerships under common ownership with the general partner interest. As a result of the Merger, the Non-Compete Agreement was terminated, effective July 20, 2018.

REVENUE FROM CONTRACTS WITH CUSTOMERS

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Revenue from Contracts with Customers

REVENUE FROM CONTRACTS WITH CUSTOMERS

Contract Assets and Contract Liabilities

The following table provides information about contract assets and contract liabilities from contracts with customers:


	2020				2019				2018
	Contract Assets		Contract Liabilities		Contract Assets		Contract Liabilities		Contract Assets		Contract Liabilities
	(Thousands of Dollars)
Balances as of January 1:
Current portion	$	2,140	$	(21,083)	$	2,066	$	(21,579)	$	1,956	$	(13,801)
Noncurrent portion	1,003		(40,289)		539		(38,945)		171		(46,361)
Held for sale	—		—		—		(25,357)		—		(302)
Total	3,143		(61,372)		2,605		(85,881)		2,127		(60,464)

Activity:
Additions	5,686		(69,830)		4,890		(52,957)		3,281		(83,243)
Transfer to accounts receivable	(4,828)		—		(4,352)		—		(2,803)		—
Transfer to revenues, including amounts reported in discontinued operations	(375)		61,646		—		77,466		—		57,826

Total	483		(8,184)		538		24,509		478		(25,417)

Balances as of December 31:
Current portion	2,694		(22,019)		2,140		(21,083)		2,066		(21,579)
Noncurrent portion	932		(47,537)		1,003		(40,289)		539		(38,945)
Held for sale	—		—		—		—		—		(25,357)
Total	$	3,626	$	(69,556)	$	3,143	$	(61,372)	$	2,605	$	(85,881)

Contract assets relate to performance obligations satisfied in advance of scheduled billings. Current contract assets are included in “Other current assets” and noncurrent contract assets are included in “Other long-term assets, net” on the consolidated balance sheets. Contract liabilities relate to payments received in advance of satisfying performance obligations under a contract, which mainly result from contracts with an incentive pricing structure, CIAC payments and contracts with MVCs. Current contract liabilities are included in “Accrued liabilities” or “Liabilities held for sale” and noncurrent contract liabilities are included in “Other long-term liabilities” on the consolidated balance sheets.

In the third quarter of 2018, we entered into an agreement whereby our customer transferred ownership of crude oil to us, and we agreed to sell the crude oil and apply the proceeds as a non-refundable, one-time payment of storage fees. At the time of the agreement, we recognized a contract liability of $37.5 million. We recognized all the revenue associated with this contract liability by the end of 2019.

In the second quarter of 2018, one customer for whom we had recorded a contract liability to perform future services elected not to extend the term of its terminal storage contract, thus reducing our future performance obligation. As a result, we adjusted the related contract liability and recognized $9.0 million in revenue.

Remaining Performance Obligations

The following table presents our estimated revenue from contracts with customers for remaining performance obligations that has not yet been recognized, representing our contractually committed revenue as of December 31, 2020 (in thousands of dollars):


2021	$	486,339
2022	354,666
2023	261,205
2024	184,862
2025	128,279
Thereafter	173,917
Total	$	1,589,268

Our contractually committed revenue, for purposes of the tabular presentation above, is generally limited to customer contracts that have fixed pricing and fixed volume terms and conditions, generally including contracts with MVC payment obligations.

Disaggregation of Revenues

The following table disaggregates our revenues:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Pipeline segment:
Crude oil pipelines	$	329,105	$	316,417	$	248,261
Refined products and ammonia pipelines (excluding lessor revenues)	387,793		376,588		362,750
Total pipeline segment revenues from contracts with customers	716,898		693,005		611,011
Lessor revenues	1,925		8,825		54
Total pipeline segment revenues	718,823		701,830		611,065

Storage segment:
Throughput terminals	136,632		114,243		83,157
Storage terminals (excluding lessor revenues)	316,496		298,984		320,582
Total storage segment revenues from contracts with customers	453,128		413,227		403,739
Lessor revenues	41,314		40,774		39,849
Total storage segment revenues	494,442		454,001		443,588

Fuels marketing segment:
Revenues from contracts with customers	268,345		342,215		465,651

Consolidation and intersegment eliminations	(46)		(25)		(42)

Total revenues	$	1,481,564	$	1,498,021	$	1,520,262

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

ALLOWANCE FOR CREDIT LOSSES

12 Months Ended

Dec. 31, 2020

Allowance for Credit Loss [Abstract]

ALLOWANCE FOR CREDIT LOSSES

The balance of and changes in the allowance for credit losses consisted of the following:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Balance as of beginning of year	$	72	$	9,412	$	9,380
Current period provision for credit losses	441		2,322		233
Write-offs charged against the allowance	(513)		(11,662)		(201)


Balance as of end of year	$	—	$	72	$	9,412

INVENTORIES

12 Months Ended

Dec. 31, 2020

Inventory Disclosure [Abstract]

INVENTORIES

Inventories consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Petroleum products	$	7,394	$	8,646
Materials and supplies	3,665		3,747
Total	$	11,059	$	12,393

We purchase petroleum products for resale. Our petroleum products consist of intermediates, gasoline, distillates and other petroleum products. Materials and supplies mainly consist of blending and additive chemicals and maintenance materials used in our pipeline and storage segments.

PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment consisted of the following:


	Estimated Useful Lives			December 31,
				2020		2019
	(Years)			(Thousands of Dollars)
Land, buildings and improvements	0	-	40	$	440,358	$	444,156
Pipelines, storage and terminals	15	-	40	5,253,507		5,162,426
Rights-of-way	20	-	40	359,441		350,026
Construction in progress		-		111,436		230,536
Total				6,164,742		6,187,144
Less accumulated depreciation and amortization				(2,207,230)		(2,068,165)
Property, plant and equipment, net				$	3,957,512	$	4,118,979

Capitalized interest costs added to property, plant and equipment, including amounts related to discontinued operations, totaled $4.9 million, $8.9 million and $7.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. Depreciation and amortization expense for property, plant and equipment totaled $228.8 million, $226.0 million and $243.5 million for the years ended December 31, 2020, 2019 and 2018, respectively, including depreciation and amortization expense reported in “(Loss) income from discontinued operations, net of tax” on the consolidated statements of (loss) income.

INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2020

Intangible Assets, Net (Excluding Goodwill) [Abstract]

INTANGIBLE ASSETS

Intangible assets consisted of the following:


	Weighted-Average Amortization Period	December 31, 2020				December 31, 2019
		Cost		Accumulated Amortization		Cost		Accumulated Amortization
	(Years)	(Thousands of Dollars)
Customer contracts and relationships	18	$	863,900	$	(235,205)	$	863,900	$	(183,832)
Other	47	2,359		(845)		2,359		(795)
Total		$	866,259	$	(236,050)	$	866,259	$	(184,627)

Intangible assets are recorded at fair value as of the date acquired. All of our intangible assets are amortized on a straight-line basis. Amortization expense for intangible assets was $51.4 million for each of the years ended December 31, 2020, 2019 and 2018. The estimated aggregate amortization expense is $51.0 million for the years 2021 and 2022, $45.0 million for 2023 and 2024 and $38.0 million for 2025.

GOODWILL

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL

The balances of and changes in the carrying amount of goodwill by segment were as follows:


	Pipeline		Storage		Total
	(Thousands of Dollars)


Balances as of January 1, 2019 and 2020	$	704,231	$	301,622	$	1,005,853





Activity for the year ended December 31, 2020:
Goodwill impairment loss on crude oil pipelines	(225,000)		—		(225,000)
Texas City Sale	—		(14,437)		(14,437)

Balances as of December 31, 2020:
Goodwill	704,231		287,185		991,416
Accumulated impairment loss	(225,000)		—		(225,000)
Net goodwill	$	479,231	$	287,185	$	766,416

Activity for the Year Ended December 31, 2020

Texas City Sale. On December 7, 2020, we completed the Texas City Sale and the goodwill associated with the sold terminals was included in the calculation of the loss on sale. Please see Note 4 for additional information on the sale.

Impairment. In March 2020, the COVID-19 pandemic and actions taken by OPEC+ resulted in severe disruptions in the capital and commodities markets, which led to significant decline in our unit price. As a result, our equity market capitalization fell significantly. The decline in crude oil prices and demand for petroleum products also led to a decline in expected earnings from some of our goodwill reporting units. These factors and others related to COVID-19 and OPEC+ caused us to conclude there were triggering events that occurred in March that required us to perform a goodwill impairment test as of March 31, 2020. We recognized a goodwill impairment charge of $225.0 million in the first quarter of 2020, which is reported in the pipeline segment. Our assessment did not identify any other reporting units at risk of a goodwill impairment.

We calculated the estimated fair value of each of our reporting units using a weighted-average of values determined from an income approach and a market approach. The income approach involves estimating the fair value of each reporting unit by discounting its estimated future cash flows using a discount rate that would be consistent with a market participant’s assumption. The market approach bases the fair value measurement on information obtained from observed stock prices of public companies and recent merger and acquisition transaction data of comparable entities. In order to estimate the fair value of goodwill, management must make certain estimates and assumptions that affect the total fair value of the reporting unit including, among other things, an assessment of market conditions, projected cash flows, discount rates and growth rates. Management’s estimates of projected cash flows related to the reporting unit include, but are not limited to, future earnings of the reporting unit, assumptions about the use or disposition of assets included in the reporting unit, estimated remaining lives of

those assets, and future expenditures necessary to maintain the assets’ existing service potential. The assumptions in the fair value measurement reflect the current market environment, industry-specific factors and company-specific factors.

The decline in expected earnings from certain of our long-lived assets was also an indicator that the carrying values of these long-lived assets may not be recoverable. Prior to performing the goodwill impairment test, we tested these long-lived assets for recoverability and determined they were fully recoverable as of March 31, 2020.

Management’s estimates are based on numerous assumptions about future operations and market conditions, which we believe to be reasonable but are inherently uncertain. The uncertainties underlying our assumptions and estimates could differ significantly from actual results, including with respect to the duration and severity of the COVID-19 pandemic.

2019 Impairment

As discussed in Note 4, in 2019, the assets and liabilities associated with the European Operations and the St. Eustatius Operations, including goodwill, were reclassified to assets and liabilities held for sale for all periods presented and are not included in the table above. In 2019, goodwill of $31.1 million associated with the bunkering operations at the St. Eustatius terminal facility, which represented all goodwill in the fuels marketing segment, was reduced to $0. Please see Note 4 for additional information.

ACCRUED LIABILITIES

12 Months Ended

Dec. 31, 2020

Accrued Liabilities, Current [Abstract]

ACCRUED LIABILITIES

Accrued liabilities consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Employee wages and benefit costs	$	27,805	$	36,704
Revenue contract liabilities	22,019		21,083
Interest rate swaps	—		19,169
Operating lease liabilities	10,890		10,416

Environmental costs	5,371		4,837

Other	11,685		16,401
Accrued liabilities	$	77,770	$	108,610

DEBT

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

DEBT

Short-term debt consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Short-term line of credit	$	—	$	5,500
Current portion of finance leases (refer to Note 16)	$	3,839	$	4,546

Long-term debt consisted of the following:


				December 31,
	Maturity			2020		2019
				(Thousands of Dollars)
Revolving Credit Agreement		2023		$	—	$	475,000
4.80% senior notes		2020		—		450,000
6.75% senior notes		2021		300,000		300,000
4.75% senior notes		2022		250,000		250,000
5.75% senior notes		2025		600,000		—
6.00% senior notes		2026		500,000		500,000
5.625% senior notes		2027		550,000		550,000
6.375% senior notes		2030		600,000		—
Subordinated Notes		2043		402,500		402,500
GoZone Bonds	2038	thru	2041	322,140		365,440
Receivables Financing Agreement		2023		57,000		62,200
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs		N/A		(42,382)		(23,301)
Total long-term debt (excluding finance leases)				3,539,258		3,331,839
Finance leases (refer to Note 16)				54,238		55,446
Less current portion				—		452,367
Long-term debt, less current portion				$	3,593,496	$	2,934,918

The long-term debt repayments (excluding finance leases) are due as follows (in thousands of dollars):


2021	$	300,000
2022	250,000
2023	57,000
2024	—
2025	600,000
Thereafter	2,374,640
Total repayments	3,581,640
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	(42,382)
Total long-term debt (excluding finance leases)	$	3,539,258

Interest payments totaled $207.2 million, $183.8 million and $190.9 million for the years ended December 31, 2020, 2019 and 2018, respectively, related to debt obligations. We amortized an aggregate of $11.4 million, $6.5 million and $7.1 million of debt issuance costs and debt discount combined for the years ended December 31, 2020, 2019 and 2018, respectively.

Term Loan Credit Agreement

On April 19, 2020, NuStar Energy and NuStar Logistics entered into an unsecured term loan credit agreement with certain lenders and Oaktree Fund Administration, LLC, as administrative agent for the lenders. The Term Loan provided for an aggregate commitment of up to $750.0 million pursuant to a three-year unsecured term loan credit facility. NuStar Logistics drew $500.0 million (the Initial Loan) on April 21, 2020 (the Initial Loan Funding Date). We utilized the proceeds from the Initial Loan, net of the original issue discount of $22.5 million (3.0% of the total commitment) and issuance costs of $14.4 million, to repay outstanding borrowings under our Revolving Credit Agreement, as defined below. The Term Loan bolstered our liquidity to address near-term senior note maturities.

On September 16, 2020, we used a portion of the net proceeds from the issuance of the 5.75% and 6.375% senior notes to repay the $500.0 million of outstanding borrowings under the Term Loan and pay related early repayment premiums totaling $97.6 million. We also recognized costs of $40.3 million related to unamortized debt issuance costs, unamortized discount and a commitment fee, which resulted in a loss from extinguishment of debt of $137.9 million in the third quarter of 2020. As of

December 31, 2020, an aggregate principal amount of $250.0 million remained available to be drawn. On February 16, 2021, we terminated the Term Loan.

Outstanding borrowings bore interest at an aggregate rate of 12.0% per annum, and the Term Loan was subject to a commitment fee in the amount of 5.0% per annum on the average daily undrawn amount of $250.0 million until April 19, 2021. Upon issuance of the $1.2 billion of senior notes in September 2020, we were required to repay outstanding borrowings under the Term Loan and pay a make-whole premium for liquidated damages and compensation for the costs of making funds available. From the Initial Loan Funding Date through the 18-month anniversary of the Initial Loan Funding Date, such premium was the sum of (i) the make-whole amount and (ii) 6.25% of the aggregate principal amount of borrowings then paid.

Revolving Credit Agreement

On March 6, 2020, NuStar Logistics amended its revolving credit agreement (the Revolving Credit Agreement) to, among other things, extend the maturity date from October 29, 2021 to October 27, 2023, reduce the total amount available for borrowing from $1.2 billion to $1.0 billion and increase the rates included in the definition of Applicable Rate contained in the Revolving Credit Agreement. On April 6, 2020, NuStar Logistics amended the Revolving Credit Agreement to allow for certain transactions related to the GoZone Bonds discussed below. On February 16, 2021, NuStar Logistics amended the Revolving Credit Agreement to, among other things, expand certain adjustments related to our maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio.

The Revolving Credit Agreement is subject to maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio requirements, which may limit the amount we can borrow to an amount less than the total amount available for borrowing. For the rolling period ending December 31, 2020, the maximum allowed consolidated debt coverage ratio (as defined in the Revolving Credit Agreement) may not exceed 5.00-to-1.00 and the minimum consolidated interest coverage ratio (as defined in the Revolving Credit Agreement), must not be less than 1.75-to-1.00. If we complete one or more acquisitions for aggregate net consideration of at least $50.0 million, our maximum consolidated debt coverage ratio will increase to 5.50-to-1.00 for two rolling periods. The Revolving Credit Agreement also contains customary restrictive covenants, such as limitations on indebtedness, liens, mergers, asset transfers and certain investing activities. As of December 31, 2020, we believe that we are in compliance with the covenants in the Revolving Credit Agreement.

As of December 31, 2020, we had $994.8 million available for borrowing and no borrowings outstanding. Letters of credit issued under the Revolving Credit Agreement totaled $5.2 million as of December 31, 2020. Letters of credit are limited to $400.0 million and also may restrict the amount we can borrow under the Revolving Credit Agreement. Obligations under the Revolving Credit Agreement are guaranteed by NuStar Energy and NuPOP.

The Revolving Credit Agreement bears interest, at our option, based on an alternative base rate or a LIBOR-based rate. The interest rate on the Revolving Credit Agreement is subject to adjustment if our debt rating is downgraded (or upgraded) by certain credit rating agencies. In August of 2020, Moody’s Investor Service Inc. downgraded our credit rating from Ba2 to Ba3. This rating downgrade caused the interest rate on our Revolving Credit Agreement to increase by 0.25% effective August 2020. The Revolving Credit Agreement is the only debt arrangement with an interest rate that is subject to adjustment if our debt rating is downgraded (or upgraded) by certain credit rating agencies. During the year ended December 31, 2020, the weighted-average interest rate related to borrowings under the Revolving Credit Agreement was 3.3%.

Notes

NuStar Logistics Senior Notes. On September 14, 2020, NuStar Logistics issued $600.0 million of 5.75% senior notes due October 1, 2025 and $600.0 million of 6.375% senior notes due October 1, 2030. We received proceeds of $1,182.0 million, net of issuance costs of $18.0 million, which we used to repay outstanding borrowings under the Term Loan, along with early repayment premiums, as well as borrowings under our Revolving Credit Agreement. The issuance of the 5.75% and 6.375% senior notes bolstered our liquidity to address our senior note maturities in early 2021 and 2022. The interest on the 5.75% and 6.375% senior notes is payable semi-annually in arrears on April 1 and October 1 of each year, beginning on April 1, 2021.

We repaid our $450.0 million of 4.8% senior notes due September 1, 2020 with borrowings under our Revolving Credit Agreement.

On May 22, 2019, NuStar Logistics issued $500.0 million of 6.0% senior notes due June 1, 2026. We received net proceeds of $491.6 million, which we used to repay outstanding borrowings under our Revolving Credit Agreement. The interest on the 6.0% senior notes is payable semi-annually in arrears on June 1 and December 1 of each year, beginning on December 1, 2019.

We repaid the $350.0 million of 7.65% senior notes on April 15, 2018 with borrowings under our Revolving Credit Agreement.

Interest is payable semi-annually in arrears for the $300.0 million of 6.75% senior notes, $250.0 million of 4.75% senior notes, $600.0 million of 5.75% senior notes, $500.0 million of 6.0% senior notes, $550.0 million of 5.625% senior notes and $600.0 million of 6.375% senior notes (collectively, the NuStar Logistics Senior Notes).

The NuStar Logistics Senior Notes do not have sinking fund requirements. These notes rank equally with existing senior unsecured indebtedness and senior to existing subordinated indebtedness of NuStar Logistics and contain restrictions on NuStar Logistics’ ability to incur secured indebtedness unless the same security is also provided for the benefit of holders of the NuStar Logistics Senior Notes. In addition, the NuStar Logistics Senior Notes limit the ability of NuStar Logistics and its subsidiaries to, among other things, incur indebtedness secured by certain liens, engage in certain sale-leaseback transactions and engage in certain consolidations, mergers or asset sales. At the option of NuStar Logistics, the NuStar Logistics Senior Notes may be redeemed in whole or in part at any time at a redemption price, plus accrued and unpaid interest to the redemption date. If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase. The NuStar Logistics Senior Notes are fully and unconditionally guaranteed by NuStar Energy and NuPOP.

We repaid our $300.0 million of 6.75% senior notes due February 1, 2021 with borrowings under our Revolving Credit Agreement; the senior notes are therefore classified as long-term debt as of December 31, 2020.

NuStar Logistics Subordinated Notes. NuStar Logistics’ $402.5 million of fixed-to-floating rate subordinated notes are due January 15, 2043 (the Subordinated Notes). The Subordinated Notes are fully and unconditionally guaranteed on an unsecured and subordinated basis by NuStar Energy and NuPOP. Effective January 15, 2018, the interest rate on the Subordinated Notes switched from a fixed annual rate of 7.625%, payable quarterly in arrears, to an annual rate equal to the sum of the three-month LIBOR for the related quarterly interest period, plus 6.734% payable quarterly, commencing April 15, 2018, unless payment is deferred in accordance with the terms of the notes. NuStar Logistics may elect to defer interest payments on the Subordinated Notes on one or more occasions for up to five consecutive years. Deferred interest will accumulate additional interest at a rate equal to the interest rate then applicable to the Subordinated Notes until paid. If NuStar Logistics elects to defer interest payments, NuStar Energy cannot declare or make cash distributions to its unitholders during the period that interest payments are deferred. As of December 31, 2020, the interest rate was 7.0%.

The Subordinated Notes do not have sinking fund requirements and are subordinated to existing senior unsecured indebtedness of NuStar Logistics and NuPOP. The Subordinated Notes do not contain restrictions on NuStar Logistics’ ability to incur additional indebtedness, including debt that ranks senior in priority of payment to the notes. In addition, the Subordinated Notes do not limit NuStar Logistics’ ability to incur indebtedness secured by liens or to engage in certain sale-leaseback transactions. Effective January 15, 2018, we may redeem the Subordinated Notes in whole or in part at a redemption price equal to 100% of the principal amount plus accrued and unpaid interest to the redemption date.

Gulf Opportunity Zone Revenue Bonds

In 2008, 2010 and 2011, the Parish of St. James, Louisiana issued Revenue Bonds Series 2008, Series 2010, Series 2010A, Series 2010B and Series 2011 associated with our St. James terminal expansions pursuant to the Gulf Opportunity Zone Act of 2005 for an aggregate $365.4 million (collectively, the GoZone Bonds). Following the issuances, the proceeds were deposited with a trustee and were disbursed to us upon our request for reimbursement of expenditures related to our St. James terminal. We did not receive any proceeds from the trustee for the years ended December 31, 2019 and 2020. On March 4, 2020, NuStar Logistics repaid $43.3 million of GoZone Bonds with unused funds, which had been held in trust. NuStar Logistics is obligated to make payments in amounts sufficient to pay the principal of, premium, if any, interest and certain other payments on, the GoZone Bonds.

On June 3, 2020, NuStar Logistics completed the reoffering and conversion of the GoZone Bonds through supplements to the original indentures governing the GoZone Bonds and supplements to the original agreements between NuStar Logistics and the Parish of St. James, which, among other things, converted the interest rate from a weekly rate to a long-term rate. In connection with the reoffering and conversion, we terminated the letters of credit previously issued by various individual banks on our

behalf to support the payments required in connection with the GoZone Bonds, and NuStar Energy and NuPOP guaranteed NuStar Logistics’ obligations with respect to the GoZone Bonds. We did not receive any proceeds from the reoffering, and the reoffering did not increase our outstanding debt.

The following table summarizes the GoZone Bonds outstanding as of December 31, 2020:

Series

Date Issued

Amount
Outstanding

Interest Rate

Mandatory
Purchase Date

Maturity Date

(Thousands of Dollars)

Series 2008

June 26, 2008

55,440

6.10

June 1, 2030

June 1, 2038

Series 2010

July 15, 2010

100,000

6.35

n/a

July 1, 2040

Series 2010A

October 7, 2010

43,300

6.35

n/a

October 1, 2040

Series 2010B

December 29, 2010

48,400

6.10

June 1, 2030

December 1, 2040

Series 2011

August 9, 2011

75,000

5.85

June 1, 2025

August 1, 2041

Total

322,140

Interest on the GoZone Bonds accrues from June 3, 2020 and is payable semi-annually on June 1 and December 1 of each year, beginning December 1, 2020. The holders of the Series 2008, Series 2010B and Series 2011 GoZone Bonds are required to tender their bonds at the applicable mandatory purchase date in exchange for 100% of the principal plus accrued and unpaid interest, after which these bonds will potentially be remarketed with a new interest rate established. Each of the Series 2010 and Series 2010A GoZone Bonds is subject to redemption on or after June 1, 2030 by the Parish of St. James, at our option, in whole or in part, at a redemption price of 100% of the principal amount to be redeemed plus accrued interest. The Series 2008, Series 2010B and Series 2011 GoZone Bonds are not subject to optional redemption.

NuStar Logistics’ agreements with the Parish of St. James related to the GoZone Bonds contain (i) customary restrictive covenants that limit the ability of NuStar Logistics and its subsidiaries, to, among other things, create liens or enter into sale-leaseback transactions, consolidations, mergers or asset sales and (ii) a change of control provision that provides each holder the right to require the trustee, with funds provided by NuStar Logistics, to repurchase all or a portion of that holder’s GoZone Bonds upon a change of control at a price equal to 101% of the aggregate principal amount repurchased, plus any accrued and unpaid interest.

Receivables Financing Agreement

NuStar Energy and NuStar Finance LLC (NuStar Finance), a special purpose entity and wholly owned subsidiary of NuStar Energy, are parties to a receivables financing agreement with third-party lenders (the Receivables Financing Agreement) and agreements with certain of NuStar Energy’s wholly owned subsidiaries (together with the Receivables Financing Agreement, the Securitization Program). On September 3, 2020, they amended the Receivables Financing Agreement to, among other things: (i) extend the maturity date from September 20, 2021 to September 20, 2023, (ii) reduce the amount available for borrowing from $125.0 million to $100.0 million, (iii) provide that the failure to satisfy the consolidated debt coverage ratio, as defined in the Revolving Credit Agreement, would constitute an Event of Default as defined in the Receivables Financing Agreement, and (iv) increase the interest rate. Under the Securitization Program, certain of NuStar Energy’s wholly owned subsidiaries (collectively, the Originators), sell their accounts receivable to NuStar Finance on an ongoing basis, and NuStar Finance provides the newly acquired accounts receivable as collateral for its revolving borrowings under the Receivables Financing Agreement. NuStar Energy provides a performance guarantee in connection with the Securitization Program. The amount available for borrowing is based on the availability of eligible receivables and other customary factors and conditions. The Securitization Program contains various customary affirmative and negative covenants and default, indemnification and termination provisions, and the Receivables Financing Agreement provides for acceleration of amounts owed upon the occurrence of certain specified events. NuStar Finance’s sole activity consists of purchasing such receivables and providing them as collateral under the Securitization Program. NuStar Finance is a separate legal entity and the assets of NuStar Finance, including these accounts receivable, are not available to satisfy the claims of creditors of NuStar Energy, the Originators or their affiliates.

Borrowings by NuStar Finance under the Receivables Financing Agreement bear interest at the applicable bank rate, as defined under the Receivables Financing Agreement. As of December 31, 2020 and 2019, accounts receivable totaling $110.6 million and $112.8 million, respectively, were included in the Securitization Program. The weighted average interest rate related to outstanding borrowings under the Securitization Program during the year ended December 31, 2020 was 1.9%.

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS

12 Months Ended

Dec. 31, 2020

Environmental Remediation Obligations [Abstract]

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS

Our operations are subject to extensive international, federal, state and local environmental laws and regulations, in the U.S. and in the other countries in which we operate, including those relating to the discharge of materials into the environment, waste management, remediation, the characteristics and composition of fuels, climate change and greenhouse gases. Our operations are also subject to extensive health, safety and security laws and regulations, including those relating to worker and pipeline safety, pipeline and storage tank integrity and operations security. The principal environmental, health, safety and security risks associated with our operations relate to unauthorized emissions into the air, releases into soil, surface water or groundwater, personal injury and property damage. We have adopted policies, practices, systems and procedures designed to comply with the laws and regulations and to help minimize and mitigate these risks, limit the liability that could result from such events, prevent material environmental or other damage, ensure the safety of our employees and the public and secure our pipelines, terminals and operations. Compliance with environmental, health, safety and security laws, regulations and related permits increases our capital expenditures and operating expenses, and violation of these laws, regulations or permits could result in significant civil and criminal liabilities, injunctions or other penalties. Future governmental action and regulatory initiatives could necessitate changes to expected operating permits and procedures, additional remedial actions or increased capital expenditures and operating costs. Risks of additional costs and liabilities are inherent to government-regulated industries, including midstream energy, and there can be no assurances that significant costs and liabilities will not be incurred in the future.

Most of our pipelines are subject to federal regulation by one or more of the following governmental agencies: The Federal Energy Regulatory Commission (the FERC), the Surface Transportation Board (the STB), the Department of Transportation (DOT), the Environmental Protection Agency (EPA) and the Department of Homeland Security. Additionally, the operations and integrity of the pipelines are subject to the respective jurisdictions of the states those lines traverse.

Environmental and safety exposures and liabilities are difficult to assess and estimate due to unknown factors such as the timing and extent of remediation, the determination of our liability in proportion to other parties, improvements in cleanup technologies and the extent to which environmental and safety laws and regulations may change in the future. Although environmental and safety costs may have a significant impact on the results of operations for any single period, we believe that such costs will not have a material adverse effect on our financial position.

The balance of and changes in the accruals for environmental matters were as follows:


	Year Ended December 31,
	2020		2019
	(Thousands of Dollars)
Balance as of the beginning of year	$	7,938	$	7,753
Additions to accrual	3,692		3,700
Payments	(3,257)		(3,515)

Balance as of the end of year	$	8,373	$	7,938

Accruals for environmental matters are included in the consolidated balance sheets as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Accrued liabilities	$	5,371	$	4,837
Other long-term liabilities	3,002		3,101
Accruals for environmental matters	$	8,373	$	7,938

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Commitments

Future minimum rental payments applicable to all noncancellable purchase obligations as of December 31, 2020 are as follows:


	Payments Due by Period
	2021		2022		2023		2024		2025		There- after		Total
	(Thousands of Dollars)
Purchase obligations	$	9,980	$	7,647	$	2,039	$	1,025	$	483	$	4,520	$	25,694

Our purchase obligations primarily consist of an eleven-year chemical supply agreement related to our pipelines that terminates in 2022 and various service agreements with information technology providers.

Contingencies

We have contingent liabilities resulting from various litigation, claims and commitments. We record accruals for loss contingencies when losses are considered probable and can be reasonably estimated. Legal fees associated with defending the Partnership in legal matters are expensed as incurred. We accrued $2.6 million and $3.7 million for contingent losses as of December 31, 2020 and 2019, respectively. The amount that will ultimately be paid related to such matters may differ from the recorded accruals, and the timing of such payments is uncertain. We evaluate each contingent loss at least quarterly, and more frequently as each matter progresses and develops over time, and we do not believe that the resolution of any particular claim or proceeding, or all matters in the aggregate, would have a material adverse effect on our results of operations, financial position or liquidity.

LEASE ASSETS AND LIABILITIES

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Lessee, operating leases [Text Block]

LEASE ASSETS AND LIABILITIES

Transition

On January 1, 2019, we adopted Accounting Standards Codification Topic 842, “Leases” (ASC Topic 842) using the modified retrospective method. Results for reporting periods beginning after January 1, 2019 are presented under ASC Topic 842. In accordance with the modified retrospective approach, prior period amounts were not adjusted and are reported under ASC Topic 840, “Leases.” As a result of the adoption of ASC Topic 842, we recorded right-of-use assets and lease liabilities of approximately $207.0 million and $192.0 million, respectively, as of January 1, 2019. The adoption of ASC Topic 842 had an immaterial impact on our results of operations and cash flows at adoption.

We elected the following practical expedients permitted under the transition guidance within the new standard:

•the package of practical expedients, which, among other things, allowed us to carry forward historical lease classification;

•the practical expedient specifically related to land easements, which, among other things, allowed us to carry forward our historical accounting treatment for existing land easement agreements;

•the lessee practical expedient to combine lease and non-lease components for all of our asset classes except the other pipeline and terminal equipment asset class; and

•the lessor practical expedient to combine lease and non-lease components and to account for the transaction based on the predominant component (i.e., ASC Topic 842 or ASC Topic 606, “Revenue from Contracts with Customers”). We apply this expedient to certain contracts in which we agree to provide both storage capacity and optional services to customers.

We record all leases on our consolidated balance sheet except for those leases with an initial term of 12 months or less, which are expensed on a straight-line basis over the lease term. We use judgment in determining the reasonably certain lease term and consider factors such as the nature and utility of the leased asset, as well as the importance of the leased asset to our operations. We calculate the present value of our lease liabilities based upon our incremental borrowing rate unless the rate implicit in the lease is readily determinable.

Lessee Arrangements

Our operating leases consist primarily of land and dock leases at various terminal facilities. As of December 31, 2020, land and dock leases have remaining terms generally of up to five years and include options to extend, some up to twenty years, which we are reasonably certain to exercise. During 2020, we modified three leases for marine vessels at our Point Tupper terminal facility in order to extend their lease terms by five years. The modifications and related remeasurements resulted in additional lease liabilities and right-of-use assets totaling $20.1 million.

The primary component of our finance lease portfolio is a dock at a terminal facility, which includes a commitment for minimum dockage and wharfage throughput volumes. The dock lease has a remaining initial term of less than one year and four additional five-year renewal periods, all of which we are reasonably certain to exercise. We historically accounted for the dock lease under legacy build-to-suit accounting guidance, which was eliminated by ASC Topic 842.

Certain of our leases are subject to variable payment arrangements, the most notable of which include:

•dockage and wharfage charges, which are based on volumes moved over leased docks and are included in our calculation of our lease payments based on minimum throughput volume requirements. We recognize charges on excess throughput volumes in profit or loss in the period in which the obligation for those payments is incurred; and

•consumer price index adjustments, which are measured and included in the calculation of our lease payments based on the consumer price index at the adoption date or, after adoption, at the commencement date. We recognize changes in lease payments as a result of changes in the consumer price index in profit or loss in the period in which those payments are made.

Right-of-use assets and lease liabilities included in our consolidated balance sheet were as follows:


		December 31,
	Balance Sheet Location	2020		2019
		(Thousands of Dollars)
Right-of-Use Assets:
Operating	Other long-term assets, net	$	87,443	$	81,219
Finance	Property, plant and equipment, net of accumulated amortization of $8,444 and $3,748	$	73,319	$	74,953

Lease Liabilities:
Operating:
Current	Accrued liabilities	$	10,890	$	10,416
Noncurrent	Other long-term liabilities	74,899		70,083
Total operating lease liabilities		$	85,789	$	80,499
Finance:
Current	Current portion of debt and finance lease obligations	$	3,839	$	4,546
Noncurrent	Long-term debt, less current portion	54,238		55,446
Total finance lease liabilities		$	58,077	$	59,992

As of December 31, 2020, maturities of our operating and finance lease liabilities were as follows:


	Operating Leases		Finance Leases
	(Thousands of Dollars)
2021	$	13,137	$	5,907
2022	12,419		5,231
2023	11,170		5,102
2024	10,294		4,622
2025	8,154		3,898
Thereafter	53,288		56,079
Total lease payments	$	108,462	$	80,839
Less: Interest	22,673		22,762
Present value of lease liabilities	$	85,789	$	58,077

Costs incurred for leases, including costs associated with discontinued operations, were as follows:


	Year Ended December 31,
	2020		2019
	(Thousands of Dollars)
Operating lease cost	$	16,814	$	29,167
Finance lease cost:
Amortization of right-of-use assets	$	4,700	$	3,748
Interest expense on lease liability	$	2,201	$	2,212
Short-term lease cost	$	15,359	$	19,140
Variable lease cost	$	8,653	$	6,990
Total lease cost	$	47,727	$	61,257

Rental expense for operating leases (pursuant to ASC Topic 840) totaled $42.9 million for the year ended December 31, 2018 including rental expense reported in “(Loss) income from discontinued operations, net of tax” on the consolidated statements of (loss) income.

The table below presents additional information regarding our leases as of and for the years ended December 31, 2020 and 2019:


	Year ended December 31,
	2020						2019
	Operating Leases			Finance Leases			Operating Leases			Finance Leases
	(Thousands of Dollars, Except Term and Rate Data)
Cash outflows from operating activities	$	14,487		$	2,208		$	27,567		$	2,027
Cash outflows from financing activities	$	—		$	4,981		$	—		$	3,700
Right-of-use assets obtained in exchange for lease liabilities	$	20,830		$	3,077		$	2,153		$	4,430
Weighted-average remaining lease term (in years)	13			19			15			20
Weighted-average discount rate	3.2		%	3.7		%	3.6		%	3.7		%

Lessee, finance leases [Text Block]

LEASE ASSETS AND LIABILITIES

Transition

We elected the following practical expedients permitted under the transition guidance within the new standard:

•the package of practical expedients, which, among other things, allowed us to carry forward historical lease classification;

•the practical expedient specifically related to land easements, which, among other things, allowed us to carry forward our historical accounting treatment for existing land easement agreements;

•the lessee practical expedient to combine lease and non-lease components for all of our asset classes except the other pipeline and terminal equipment asset class; and

Lessee Arrangements

Certain of our leases are subject to variable payment arrangements, the most notable of which include:

Right-of-use assets and lease liabilities included in our consolidated balance sheet were as follows:


		December 31,
	Balance Sheet Location	2020		2019
		(Thousands of Dollars)
Right-of-Use Assets:
Operating	Other long-term assets, net	$	87,443	$	81,219
Finance	Property, plant and equipment, net of accumulated amortization of $8,444 and $3,748	$	73,319	$	74,953

Lease Liabilities:
Operating:
Current	Accrued liabilities	$	10,890	$	10,416
Noncurrent	Other long-term liabilities	74,899		70,083
Total operating lease liabilities		$	85,789	$	80,499
Finance:
Current	Current portion of debt and finance lease obligations	$	3,839	$	4,546
Noncurrent	Long-term debt, less current portion	54,238		55,446
Total finance lease liabilities		$	58,077	$	59,992

As of December 31, 2020, maturities of our operating and finance lease liabilities were as follows:


	Operating Leases		Finance Leases
	(Thousands of Dollars)
2021	$	13,137	$	5,907
2022	12,419		5,231
2023	11,170		5,102
2024	10,294		4,622
2025	8,154		3,898
Thereafter	53,288		56,079
Total lease payments	$	108,462	$	80,839
Less: Interest	22,673		22,762
Present value of lease liabilities	$	85,789	$	58,077

Costs incurred for leases, including costs associated with discontinued operations, were as follows:


	Year Ended December 31,
	2020		2019
	(Thousands of Dollars)
Operating lease cost	$	16,814	$	29,167
Finance lease cost:
Amortization of right-of-use assets	$	4,700	$	3,748
Interest expense on lease liability	$	2,201	$	2,212
Short-term lease cost	$	15,359	$	19,140
Variable lease cost	$	8,653	$	6,990
Total lease cost	$	47,727	$	61,257

The table below presents additional information regarding our leases as of and for the years ended December 31, 2020 and 2019:


	Year ended December 31,
	2020						2019
	Operating Leases			Finance Leases			Operating Leases			Finance Leases
	(Thousands of Dollars, Except Term and Rate Data)
Cash outflows from operating activities	$	14,487		$	2,208		$	27,567		$	2,027
Cash outflows from financing activities	$	—		$	4,981		$	—		$	3,700
Right-of-use assets obtained in exchange for lease liabilities	$	20,830		$	3,077		$	2,153		$	4,430
Weighted-average remaining lease term (in years)	13			19			15			20
Weighted-average discount rate	3.2		%	3.7		%	3.6		%	3.7		%

Lessor, operating leases [Text Block]

Lessor Arrangements

We have entered into certain revenue arrangements where we are considered to be the lessor. Under the largest of these arrangements, we lease certain of our storage tanks in exchange for a fixed fee, subject to an annual consumer price index adjustment. The operating leases commenced on January 1, 2017, and have initial terms of 10 years with successive automatic renewal terms. We recognized lease revenues from these leases of $41.3 million and $40.8 million for the years ended December 31, 2020 and 2019, respectively, which are included in “Service revenues” in the consolidated statements of (loss) income. As of December 31, 2020, we expect to receive minimum lease payments totaling $234.8 million, based upon the consumer price index as of the adoption date. We will recognize these payments ratably over the remaining initial lease term.

The table below presents cost, accumulated depreciation and useful life information related to our storage lease assets, which are included in our “Pipeline, storage and terminals” asset class within property, plant and equipment, as of December 31, 2020 and 2019:


	Estimated Useful Life	December 31,
		2020		2019
	(Years)	(Thousands of Dollars)
Lease storage assets, at cost	30	$	241,664	238,204
Less accumulated depreciation		(130,217)		(121,545)
Lease storage assets, net		$	111,447	$	116,659

DERIVATIVES AND FAIR VALUE MEASUREMENTS

12 Months Ended

Dec. 31, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

FAIR VALUE MEASUREMENTS

DERIVATIVES AND FAIR VALUE MEASUREMENTS

Derivative Instruments

We utilize various derivative instruments to manage our exposure to interest rate risk and commodity price risk. Our risk management policies and procedures are designed to monitor interest rates, futures and swap positions and over-the-counter positions, as well as physical commodity volumes, grades, locations and delivery schedules, to help ensure that our hedging activities address our market risks.

Commodity Price Risk. The results of operations for the fuels marketing segment depend largely on the margin between our cost and the sales prices of the products we market. Therefore, the results of operations for this segment are more sensitive to changes in commodity prices compared to the operations of the pipeline and storage segments. Since our fuels marketing operations expose us to commodity price risk, we enter into derivative instruments to mitigate the effect of commodity price fluctuations on our operations. Derivative financial instruments associated with commodity price risk with respect to our petroleum product inventories and related firm commitments to purchase and/or sell such inventories were not material for any period presented.

Interest Rate Risk. We were a party to certain interest rate swap agreements to manage our exposure to changes in interest rates, which consisted of forward-starting interest rate swap agreements related to forecasted debt issuances. We entered into these swaps in order to hedge the risk of fluctuations in the required interest payments attributable to changes in the benchmark interest rate during the period from the effective date of the swap to the issuance of the forecasted debt. Under the terms of the swaps, we paid a weighted-average fixed rate and received a rate based on the three-month USD LIBOR. These swaps qualified as cash flow hedges, and we designated them as such. We recorded mark-to-market adjustments as a component of AOCI, and the amount in AOCI is recognized in “Interest expense, net” as the forecasted interest payments occur or if the interest payments are probable not to occur. In June 2020, in connection with the reoffering and conversion of the GoZone Bonds, we terminated forward-starting interest rate swaps with an aggregate notional amount of $250.0 million and paid $49.2 million, which will be amortized into “Interest expense, net” as the related forecasted interest payments occur. In April 2018, in connection with the maturity of the 7.65% senior notes due April 15, 2018, we terminated forward-starting interest rate swaps with an aggregate notional amount of $350.0 million and received $8.0 million. The termination payments and receipts are included in cash flows from financing activities on the consolidated statements of cash flows.

The remaining fair value amounts associated with unwound interest rate swap agreements are presented in the table below. These amounts are amortized ratably over the remaining life of the related debt instrument into “Interest expense, net” on the consolidated statements of (loss) income.


		December 31,
Unwound Interest Rate Swap Agreements	Balance Sheet Location	2020		2019
		(Thousands of Dollars)
Fixed-to-floating	Current portion of long-term debt	$	—	$	2,755
Fixed-to-floating	Long-term debt, less current portion	$	1,363	$	2,568
Forward-starting	Accumulated other comprehensive (loss) income	$	(42,150)	$	3,045

Our forward-starting interest rate swaps had the following impact on earnings:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
(Loss) gain recognized in other comprehensive income (loss) on derivative	$	(30,291)	$	(19,045)	$	17,912
Loss reclassified from AOCI into interest expense, net	$	(4,265)	$	(3,814)	$	(5,499)

As of December 31, 2020, we expect to reclassify a loss of $5.4 million to “Interest expense, net” within the next twelve months associated with unwound forward-starting interest rate swap agreements.

Fair Value Measurements

We segregate the inputs used in measuring fair value into three levels: Level 1, defined as observable inputs such as quoted prices for identical assets or liabilities in active markets; Level 2, defined as inputs other than quoted prices in active markets

that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets that are not active; and Level 3, defined as unobservable inputs for which little or no market data exists. We consider counterparty credit risk and our own credit risk in the determination of all estimated fair values.

Recurring Fair Value Measurements. Prior to the termination of our forward-starting interest rate swaps, we estimated the fair value using discounted cash flows, which use observable inputs such as time to maturity and market interest rates, and, therefore, we included interest rate swaps in Level 2 of the fair value hierarchy. As of December 31, 2019, the fair value of our forward-starting interest rate swap agreements included in “Accrued liabilities” on our consolidated balance sheet was $19.2 million, with an aggregate notional amount of $250.0 million.

Fair Value of Financial Instruments

We recognize cash equivalents, receivables, payables and debt in our consolidated balance sheets at their carrying amounts. The fair values of these financial instruments, except for long-term debt other than finance leases, approximate their carrying amounts. The estimated fair values and carrying amounts of the long-term debt, including the current portion and excluding finance leases, were as follows:


	December 31, 2020		December 31, 2019
	(Thousands of Dollars)
Fair value	$	3,799,378	$	3,442,001
Carrying amount	$	3,539,258	$	3,331,839

We have estimated the fair value of our publicly traded notes based upon quoted prices in active markets; therefore, we determined that the fair value of our publicly traded notes falls in Level 1 of the fair value hierarchy. With regard to our other debt, for which a quoted market price is not available, we have estimated the fair value using a discounted cash flow analysis using current incremental borrowing rates for similar types of borrowing arrangements and determined that the fair value falls in Level 2 of the fair value hierarchy. The carrying value includes net fair value adjustments, unamortized discounts and unamortized debt issuance costs.

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS	12 Months Ended
SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS	Dec. 31, 2020
Temporary Equity Disclosure [Abstract]
SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS	SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Purchase Agreement and Issuance of Series D Preferred Units On June 26, 2018, the Partnership entered into a purchase agreement (the Series D Preferred Unit Purchase Agreement) with investment funds, accounts and entities (collectively, the Purchasers) managed by EIG Management Company, LLC and FS/EIG Advisors, LLC to issue and sell $590.0 million of Series D Cumulative Convertible Preferred Units (Series D Preferred Units) in a private placement. The Partnership issued a total of 23,246,650 Series D Preferred Units to the Purchasers at a price of $25.38 per Series D Preferred Unit (the Series D Preferred Unit Purchase Price). At the initial closing on June 29, 2018 (the Initial Closing), the Purchasers purchased 15,760,441 Series D Preferred Units for $400.0 million, and we received net proceeds of $370.7 million. The Purchasers purchased the remaining 7,486,209 Series D Preferred Units for $190.0 million at a second closing on July 13, 2018. The net proceeds to the Partnership from the sale of the Series D Preferred Units of $555.8 million, including deductions for a 3.5% transaction fee of $20.7 million paid to the Purchasers and other issuance costs of $13.5 million, were used for general partnership purposes, including repayment of outstanding borrowings under our Revolving Credit Agreement. Series D Preferred Units Rights At the Initial Closing and pursuant to the Series D Preferred Unit Purchase Agreement, the Partnership amended and restated its partnership agreement to authorize and establish the rights, preferences and privileges of the Series D Preferred Units. The Series D Preferred Units rank equal to other classes of preferred units and senior to common units in the Partnership with respect to distribution rights and rights upon liquidation. The Series D Preferred Units generally will vote on an as-converted basis with the common units and will have certain class voting rights with respect to a limited number of matters as set forth in the partnership agreement. Series D Preferred Units Distributions Distributions on the Series D Preferred Units are payable out of any legally available funds, accrue and are cumulative from the issuance dates and are payable on the 15th day (or next business day) of each of March, June, September and December, beginning September 17, 2018, to holders of record on the first business day of each payment month. The distribution rates on the Series D Preferred Units are as follows: (i) 9.75%, or $57.6 million, per annum ($0.619 per unit per distribution period) for the first two years; (ii) 10.75%, or $63.4 million, per annum ($0.682 per unit per distribution period) for years three through five; and (iii) the greater of 13.75%, or $81.1 million, per annum ($0.872 per unit per distribution period) or the distribution per common unit thereafter. While the Series D Preferred Units are outstanding, the Partnership will be prohibited from paying distributions on any junior securities, including the common units, unless full cumulative distributions on the Series D Preferred Units (and any parity securities) have been, or contemporaneously are being, paid or set aside for payment through the most recent Series D Preferred Unit distribution payment date. Any Series D Preferred Unit distributions in excess of $0.635 per unit may be paid, in the Partnership’s sole discretion, in additional Series D Preferred Units, with the remainder paid in cash. If we fail to pay in full any Series D Preferred Unit distribution amount, then, until we pay such distributions in full, the applicable distribution rate for each of those distribution periods shall be increased by $0.048 per Series D Preferred Unit. In addition, if we fail to pay in full any Series D Preferred Unit distribution amount for three consecutive distribution periods, then until we pay such distributions in full: (i) each holder of the Series D Preferred Units may elect to convert its Series D Preferred Units into common units on a one-for-one basis, plus any unpaid Series D distributions, (ii) one person selected by the holders holding a majority of the outstanding Series D Preferred Units shall become an additional member of our board of directors and (iii) we will not be permitted to incur any indebtedness (as defined in the Revolving Credit Agreement) or engage in any acquisitions or asset sales in excess of $50.0 million without the consent of the holders holding a majority of the outstanding Series D Preferred Units. In addition, we will permanently lose the ability to pay any part of the distributions on the Series D Preferred Units in the form of additional Series D Preferred Units. In January 2021, our board of directors declared a distribution of $0.682 per Series D Preferred Unit to be paid on March 15, 2021. Series D Preferred Units Conversion and Redemption Features On or after June 29, 2020, each holder of Series D Preferred Units may convert all or any portion of its Series D Preferred Units into common units on a one-for-one basis (plus any unpaid Series D distributions), subject to anti-dilution adjustments, at any time, but not more than once per quarter, so long as any conversion is for at least $50.0 million based on the Series D Preferred Unit Purchase Price (or such lesser amount representing all of a holder’s Series D Preferred Units). The Partnership may redeem all or any portion of the Series D Preferred Units, in an amount not less than $50.0 million for cash at a redemption price equal to, as applicable: (i) $31.73 per Series D Preferred Unit at any time on or after June 29, 2023 but prior to June 29, 2024; (ii) $30.46 per Series D Preferred Unit at any time on or after June 29, 2024 but prior to June 29, 2025; (iii) $29.19 per Series D Preferred Unit at any time on or after June 29, 2025; plus, in each case, the sum of any unpaid distributions on the applicable Series D Preferred Unit plus the distributions prorated for the number of days elapsed (not to exceed 90) in the period of redemption (Series D Partial Period Distributions). The holders have the option to convert the units prior to such redemption as discussed above. Additionally, at any time on or after June 29, 2028, each holder of Series D Preferred Units will have the right to require the Partnership to redeem all of the Series D Preferred Units held by such holder at a redemption price equal to $29.19 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions. If a holder of Series D Preferred Units exercises its redemption right, the Partnership may elect to pay up to 50% of such amount in common units (which shall be valued at 93% of a volume-weighted average trading price of the common units); provided, that the common units to be issued do not, in the aggregate, exceed 15% of NuStar Energy’s common equity market capitalization at the time. Series D Preferred Units Change of Control Upon certain events involving a change of control, each holder of the Series D Preferred Units may elect to: (i) convert its Series D Preferred Units into common units on a one-for-one basis, plus any unpaid Series D distributions; (ii) require the Partnership to redeem its Series D Preferred Units for an amount equal to the sum of (a) $29.82 per Series D Preferred Unit plus (b) any unpaid Series D distributions plus (c) the applicable distribution amount for the distribution periods ending after the change of control event and prior to (but including) the fourth anniversary of the Initial Closing; (iii) if the Partnership is the surviving entity and its common units continue to be listed, continue to hold its Series D Preferred Units; or (iv) if the Partnership will not be the surviving entity, or it will be the surviving entity but its common units will cease to be listed, require the Partnership to use its commercially reasonable efforts to deliver a security in the surviving entity that has substantially similar terms as the Series D Preferred Units; however, if the Partnership is unable to deliver a mirror security, each holder is still entitled to option (i) or (ii) above. Registration Rights Agreement On June 29, 2018, in connection with the Initial Closing and pursuant to the Series D Preferred Unit Purchase Agreement, the Partnership entered into a Registration Rights Agreement (the Registration Rights Agreement) with the Purchasers relating to the registration of the Series D Preferred Units and common units issuable upon conversion of the Series D Preferred Units (the Common Unit Registrable Securities, and, collectively with the Series D Preferred Units, the Registrable Securities). Pursuant to the Registration Rights Agreement, the Partnership is required to use its commercially reasonable efforts to file a registration statement and to cause such registration statement to become effective: (i) with respect to the Common Unit Registrable Securities, no later than one year after the Initial Closing; and (ii) with respect to the Series D Preferred Units, after the second anniversary of the Initial Closing, no later than one year after receipt by the Partnership of a written request from holders holding a majority of the Series D Preferred Units to register the Series D Preferred Units. In April 2019, the Securities and Exchange Commission declared effective the registration statement on Form S-3 filed by NuStar Energy to register the Common Unit Registrable Securities. With respect to the Series D Preferred Units, if the Partnership fails to cause such registration statement to become effective by the applicable date, the Partnership will be required to pay certain amounts to the holders of the Registrable Securities as liquidated damages. Series D Preferred Units Accounting Treatment The Series D Preferred Units include redemption provisions at the option of the holders of the Series D Preferred Units and upon a Series D Change of Control (as defined in the partnership agreement), which are outside the Partnership’s control. Therefore, the Series D Preferred Units are presented in the mezzanine section of the consolidated balance sheets. The Series D Preferred Units have been recorded at their issuance date fair value, net of issuance costs. We reassess the presentation of the Series D Preferred Units in our consolidated balance sheets on a quarterly basis. The Series D Preferred Units are subject to accretion from their carrying value at the issuance date to the redemption value, which is based on the redemption right of the Series D Preferred Unit holders that may be exercised at any time on or after June 29, 2028, using the effective interest method over a period of ten years. In the calculation of net income per unit, the accretion is treated in the same manner as a distribution and deducted from net income to arrive at net income attributable to common units.

PARTNERS' EQUITY

12 Months Ended

Dec. 31, 2020

Partners' Capital Notes [Abstract]

PARTNERS' EQUITY

PARTNERS’ EQUITY

Please refer to Note 5 for a discussion of the Merger.

Partnership Agreement Amendments

In the third quarter of 2018, NuStar Energy’s partnership agreement was amended and restated to, among other things, (i) cancel the incentive distribution rights held by our general partner, (ii) convert the 2% general partner interest in NuStar Energy held by our general partner into a non-economic management interest and (iii) provide the holders of our common units with voting rights in the election of the members of the board of directors of NuStar GP, LLC, beginning at the annual meeting in 2019. The partnership agreement was also amended and restated in the second quarter of 2018 in connection with the issuance of our Series D Preferred Units discussed in Note 18.

Series A, B and C Preferred Units

The following is a summary of our Series A, Series B and Series C Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (collectively the Series A, B and C Preferred Units) issued and outstanding as of December 31, 2020:


Units	Original Issuance Date	Number of Units Issued and Outstanding	Price per Unit		Fixed Distribution Rate per Annum (as a Percentage of the $25.00 Liquidation Preference per Unit)		Fixed Distribution Rate per Unit per Annum		Fixed Distribution per Annum (in thousands)		Optional Redemption Date/Date at Which Distribution Rate Becomes Floating	Floating Annual Rate (as a Percentage of the $25.00 Liquidation Preference per Unit)
Series A Preferred Units	November 25, 2016	9,060,000	$	25.00	8.50	%	$	2.125	$	19,252	December 15, 2021	Three-month LIBOR plus 6.766%
Series B Preferred Units	April 28, 2017	15,400,000	$	25.00	7.625	%	$	1.90625	$	29,357	June 15, 2022	Three-month LIBOR plus 5.643%
Series C Preferred Units	November 30, 2017	6,900,000	$	25.00	9.00	%	$	2.25	$	15,525	December 15, 2022	Three-month LIBOR plus 6.88%

We may redeem any of our outstanding Series A, B and C Preferred Units at any time on or after the optional redemption date set forth above for each series of the Series A, B and C Preferred Units, in whole or in part, at a redemption price of $25.00 per unit plus an amount equal to all accumulated and unpaid distributions to, but not including, the date of redemption, whether or not declared. We may also redeem the Series A, B and C Preferred Units upon the occurrence of certain rating events or a change of control as defined in our partnership agreement. In the case of the latter instance, if we choose not to redeem the Series A, B and C Preferred Units, those preferred unitholders may have the ability to convert their Series A, B and C Preferred Units to common units at the then applicable conversion rate. Holders of the Series A, B and C Preferred Units have no voting rights except for certain exceptions set forth in our partnership agreement.

Distributions on the Series A, B and C Preferred Units are payable out of any legally available funds, accrue and are cumulative from the original issuance dates, and are payable on the 15th day (or the next business day) of each of March, June, September and December of each year to holders of record on the first business day of each payment month. The Series A, B and C Preferred Units rank equal to each other and to the Series D Preferred Units, and senior to all of our other classes of equity securities with respect to distribution rights and rights upon liquidation.

In January 2021, our board of directors declared quarterly distributions with respect to the Series A, B and C Preferred Units to be paid on March 15, 2021.

Common Units and General Partner

Issuances of Common Units. In the fourth quarter of 2019, we issued 527,426 common units at a price of $28.44 per unit to William E. Greehey, Chairman of the Board of Directors of NuStar GP, LLC. We used the proceeds of $15.0 million from the sale of these units for general partnership purposes.

As a result of the Merger discussed in Note 5, we issued approximately 13.4 million incremental NuStar Energy common units in the third quarter of 2018, in exchange for the previously outstanding Holdings units.

In the second quarter of 2018, we issued 413,736 common units at a price of $24.17 per unit to William E. Greehey. We used the proceeds of $10.2 million from the sale of these units, including a contribution of $0.2 million from our general partner to maintain the 2% general partner economic interest it owned at that time, for general partnership purposes.

The following table shows the balance of and changes in the number of our common units outstanding:


	Year Ended December 31,
	2020	2019	2018
Balance as of the beginning of year	108,527,806	107,225,156	93,176,683
Issuance of units	—	527,426	413,736
Unit-based compensation (refer to Note 23 for discussion)	940,321	775,224	225,144
Merger (refer to Note 5 for discussion)	—	—	13,409,593
Balance as of the end of year	109,468,127	108,527,806	107,225,156

Cash Distributions. We make quarterly distributions to common unitholders, and, prior to the Merger, made quarterly distributions to the general partner of 100% of our “Available Cash,” generally defined as cash receipts less cash disbursements, including distributions to our preferred units, and cash reserves established by the general partner, in its sole discretion. These quarterly distributions are declared and paid within 45 days subsequent to each quarter-end. The common unitholders receive a distribution each quarter as determined by the board of directors, subject to limitation by the distributions in arrears, if any, on our preferred units.

The following table summarizes information about cash distributions to our common limited partners applicable to the period in which the distributions were earned:


	Cash Distributions Per Unit		Total Cash Distributions		Record Date	Payment Date
			(Thousands of Dollars)
Quarter ended:
December 31, 2020	$	0.40	$	43,787	February 8, 2021	February 12, 2021
September 30, 2020	0.40		43,678		November 6, 2020	November 13, 2020
June 30, 2020	0.40		43,678		August 7, 2020	August 13, 2020
March 31, 2020	0.40		43,730		May 11, 2020	May 15, 2020
Year ended December 31, 2020	$	1.60	$	174,873

Year ended December 31, 2019	$	2.40	$	259,136
Year ended December 31, 2018	$	2.40	$	248,705

Because the Merger was effective prior to the record date for the distribution for the second quarter of 2018, the general partner received no distributions after the first quarter of 2018 distribution. For the year ended December 31, 2018, the general partner earned $1.1 million in distributions related to the first quarter of 2018.

Accumulated Other Comprehensive Income (Loss)

The balance of and changes in the components included in AOCI were as follows:


	Foreign Currency Translation		Cash Flow Hedges		Pension and Other Postretirement Benefits		Total
	(Thousands of Dollars)
Balance as of January 1, 2018	$	(51,603)	$	(24,304)	$	(9,020)	$	(84,927)
Other comprehensive (loss) income before reclassification adjustments	(13,880)		17,912		3,282		7,314
Sale of European Operations reclassified into other income, net	18,124		—		—		18,124
Net gain on pension costs reclassified into other income, net	—		—		(814)		(814)
Net loss on cash flow hedges reclassified into interest expense, net	—		5,499		—		5,499
Other	60		—		(134)		(74)
Other comprehensive income	4,304		23,411		2,334		30,049
Balance as of December 31, 2018	(47,299)		(893)		(6,686)		(54,878)
Other comprehensive income (loss) before reclassification adjustments	3,527		(19,045)		1,000		(14,518)
Net gain on pension costs reclassified into other income, net	—		—		(2,314)		(2,314)
Net loss on cash flow hedges reclassified into interest expense, net	—		3,814		—		3,814

Other comprehensive income (loss)	3,527		(15,231)		(1,314)		(13,018)
Balance as of December 31, 2019	(43,772)		(16,124)		(8,000)		(67,896)
Other comprehensive income (loss) before reclassification adjustments	1,410		(30,291)		(2,924)		(31,805)
Net gain on pension costs reclassified into other income, net	—		—		(1,220)		(1,220)
Net loss on cash flow hedges reclassified into interest expense, net	—		4,265		—		4,265

Other comprehensive income (loss)	1,410		(26,026)		(4,144)		(28,760)
Balance as of December 31, 2020	$	(42,362)	$	(42,150)	$	(12,144)	$	(96,656)

NET (LOSS) INCOME PER COMMON UNIT

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

NET (LOSS) INCOME PER UNIT

NET (LOSS) INCOME PER COMMON UNIT

As discussed in Note 18, the Series D Preferred Units are convertible into common units at the option of the holder at any time on or after June 29, 2020. As such, we calculated the dilutive effect of the Series D Preferred Units using the if-converted method. The effect of the assumed conversion of the Series D Preferred Units outstanding was antidilutive for each of the years ended December 31, 2020, 2019 and 2018; therefore, we did not include such conversion in the computation of diluted net (loss) income per common unit.

Contingently issuable performance units are included as dilutive potential common units if it is probable that the performance measures will be achieved, unless to do so would be antidilutive. Refer to Note 23 for additional discussion.

The following table details the calculation of net loss per common unit:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars, Except Unit and Per Unit Data)
Net (loss) income	$	(198,983)	$	(105,693)	$	205,794
Distributions to preferred limited partners	(124,882)		(121,693)		(92,540)
Distributions to general partner	—		—		(1,141)
Distributions to common limited partners	(174,873)		(259,136)		(248,705)
Distribution equivalent rights to restricted units	(2,093)		(2,659)		(2,045)
Distributions in excess of (loss) income	$	(500,831)	$	(489,181)	$	(138,637)

Distributions to common limited partners	$	174,873	$	259,136	$	248,705
Allocation of distributions in excess of (loss) income	(500,831)		(489,181)		(138,659)
Series D Preferred Unit accretion (refer to Note 18)	(17,626)		(18,085)		(8,195)
Loss to common unitholders attributable to the Merger (refer to Note 5)	—		—		(377,079)
Net loss attributable to common units	$	(343,584)	$	(248,130)	$	(275,228)

Basic weighted-average common units outstanding	109,155,117		107,789,030		99,490,495

Diluted common units outstanding:
Basic weighted-average common units outstanding	109,155,117		107,789,030		99,490,495
Effect of dilutive potential common units	—		65,669		40,677
Diluted weighted-average common units outstanding	109,155,117		107,854,699		99,531,172

Basic and diluted net loss per common unit	$	(3.15)	$	(2.30)	$	(2.77)

SUPPLEMENTAL CASH FLOW INFORMATION

12 Months Ended

Dec. 31, 2020

Supplemental Cash Flow Information [Abstract]

STATEMENTS OF CASH FLOWS

SUPPLEMENTAL CASH FLOW INFORMATION

Changes in current assets and current liabilities were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Decrease (increase) in current assets:
Accounts receivable	$	14,589	$	(23,480)	$	22,482
Receivable from related party	—		—		160
Inventories	1,340		(866)		3,819

Prepaid and other current assets	(3,326)		(5,103)		3,694
Increase (decrease) in current liabilities:
Accounts payable	(25,455)		8,068		8,003

Accrued interest payable	12,922		1,632		(4,279)
Accrued liabilities	7,886		(19,740)		39,862
Taxes other than income tax	3,972		(5,276)		4,521

Changes in current assets and current liabilities	$	11,928	$	(44,765)	$	78,262

The above changes in current assets and current liabilities differ from changes between amounts reflected in the applicable consolidated balance sheets due to:

•the change in the amount accrued for capital expenditures;

•the effect of foreign currency translation;

•changes in the fair values of our interest rate swap agreements prior to termination;

•the effect of accrued compensation expense paid with fully vested common unit awards;

•the recognition of lease liabilities upon the adoption of ASC Topic 842;

•the reclassification of certain assets and liabilities to “Assets held for sale” and “Liabilities held for sale” on the consolidated balance sheets (please refer to Note 4 for additional discussion); and

•current assets and current liabilities acquired and disposed of during the period.

Cash flows related to interest and income taxes were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Cash paid for interest, net of amount capitalized	$	204,511	$	176,859	$	183,078
Cash paid for income taxes, net of tax refunds received	$	3,260	$	6,817	$	8,535

Restricted cash is included in "Other long-term assets, net" on the consolidated balance sheets. “Cash, cash equivalents and restricted cash” on the consolidated statements of cash flows was included in the consolidated balance sheets as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Cash and cash equivalents	$	153,625	$	16,192
Other long-term assets, net	8,801		8,788
Cash, cash equivalents and restricted cash	$	162,426	$	24,980

EMPLOYEE BENEFIT PLANS

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

EMPLOYEE BENEFIT PLANS

Thrift Plans

The NuStar Thrift Plan (the Thrift Plan) is a qualified defined contribution plan that became effective June 26, 2006. Participation in the Thrift Plan is voluntary and open to substantially all our domestic employees upon their dates of hire. Thrift Plan participants can contribute from 1% up to 30% of their total annual compensation to the Thrift Plan in the form of pre-tax and/or after tax employee contributions. We make matching contributions in an amount equal to 100% of each participant’s employee contributions up to a maximum of 6% of the participant’s total annual compensation. The matching contributions to the Thrift Plan for the years ended December 31, 2020, 2019 and 2018 totaled $7.8 million, $7.6 million and $7.4 million, respectively.

The NuStar Excess Thrift Plan (the Excess Thrift Plan) is a nonqualified deferred compensation plan that became effective July 1, 2006. The Excess Thrift Plan provides benefits to those employees whose compensation and/or annual contributions under the Thrift Plan are subject to the limitations applicable to qualified retirement plans under the Code.

We also maintain other defined contribution plans for certain international employees located in Canada. We maintained plans for international employees in the Caribbean Netherlands, United Kingdom and Netherlands prior to the St. Eustatius Disposition and the European Disposition on July 29, 2019 and November 30, 2018, respectively. For the years ended December 31, 2020, 2019 and 2018, our costs for these plans totaled $0.5 million, $0.9 million and $2.5 million, respectively.

Pension and Other Postretirement Benefits

The NuStar Pension Plan (the Pension Plan) is a qualified non-contributory defined benefit pension plan that provides eligible U.S. employees with retirement income as calculated under a cash balance formula. Under the cash balance formula, benefits are determined based on age, years of vesting service and interest credits, and employees become fully vested in their benefits upon attaining three years of vesting service. Prior to January 1, 2014, eligible employees were covered under either a cash balance formula or a final average pay formula (FAP). Effective January 1, 2014, the Pension Plan was amended to freeze the FAP benefits as of December 31, 2013, and going forward, all eligible employees are covered under the cash balance formula discussed above.

We also maintain an excess pension plan (the Excess Pension Plan), which is a nonqualified deferred compensation plan that provides benefits to a select group of management or other highly compensated employees. Neither the Excess Thrift Plan nor the Excess Pension Plan is intended to constitute either a qualified plan under the provisions of Section 401 of the Code or a funded plan subject to the Employee Retirement Income Security Act.

The Pension Plan and Excess Pension Plan are collectively referred to as the Pension Plans in the tables and discussion below. Our other postretirement benefit plans include a contributory medical benefits plan for U.S. employees who retired prior to April 1, 2014 and, for employees who retire on or after April 1, 2014, a partial reimbursement for eligible third-party health care premiums. We use December 31 as the measurement date for our pension and other postretirement plans.

The changes in the benefit obligation, the changes in fair value of plan assets, the funded status and the amounts recognized in the consolidated balance sheets for our Pension Plans and other postretirement benefit plans as of and for the years ended December 31, 2020 and 2019 were as follows:


	Pension Plans				Other Postretirement Benefit Plans
	2020		2019		2020		2019
	(Thousands of Dollars)
Change in benefit obligation:
Benefit obligation, January 1	$	167,257	$	141,833	$	13,196	$	10,908
Service cost	9,174		9,549		529		431
Interest cost	4,693		5,480		399		453
Benefits paid	(9,520)		(7,109)		(281)		(217)
Participant contributions	—		—		44		62
Actuarial loss	15,081		17,504		793		1,559
Benefit obligation, December 31	$	186,685	$	167,257	$	14,680	$	13,196
Change in plan assets:
Plan assets at fair value, January 1	$	159,036	$	126,949	$	—	$	—
Actual return on plan assets	21,758		28,064		—		—
Employer contributions	11,453		11,132		237		155
Benefits paid	(9,520)		(7,109)		(281)		(217)
Participant contributions	—		—		44		62
Plan assets at fair value, December 31	$	182,727	$	159,036	$	—	$	—
Reconciliation of funded status:
Fair value of plan assets at December 31	$	182,727	$	159,036	$	—	$	—
Less: Benefit obligation at December 31	186,685		167,257		14,680		13,196
Funded status at December 31	$	(3,958)	$	(8,221)	$	(14,680)	$	(13,196)
Amounts recognized in the consolidated balance sheets (a):
Accrued liabilities	$	(382)	$	(303)	$	(352)	$	(368)
Other long-term liabilities	(3,576)		(7,918)		(14,328)		(12,828)
Net pension liability	$	(3,958)	$	(8,221)	$	(14,680)	$	(13,196)

Accumulated benefit obligation	$	181,263	$	164,183	$	14,680	$	13,196

(a)For the Pension Plan, since assets exceed the present value of expected benefit payments for the next 12 months, all of the liability is noncurrent. For the Excess Pension Plan and the other postretirement benefit plans, since there are no assets, the current liability is the present value of expected benefit payments for the next 12 months; the remainder is noncurrent.

The actuarial loss related to the benefit obligation for our pension plans was primarily attributable to a decrease in the discount rates used to determine the benefit obligation from 3.34% to 2.84% in 2020 and from 4.40% to 3.34% in 2019. The fair value of our plan assets is affected by the return on plan assets resulting primarily from the performance of equity and bond markets during the period.

The Excess Pension Plan has no plan assets and an accumulated benefit obligation of $3.8 million and $3.7 million as of December 31, 2020 and 2019, respectively. The accumulated benefit obligation is the present value of benefits earned to date, assuming no future salary increases, and for the Excess Pension Plan, approximates the projected benefit obligation.

The components of net periodic benefit cost (income) related to our Pension Plans and other postretirement benefit plans were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
	(Thousands of Dollars)
Service cost	$	9,174	$	9,549	$	9,621	$	529	$	431	$	504
Interest cost	4,693		5,480		4,824		399		453		429
Expected return on plan assets	(8,972)		(8,015)		(7,417)		—		—		—
Amortization of prior service credit	(2,057)		(2,057)		(2,057)		(1,145)		(1,145)		(1,145)
Amortization of net actuarial loss	1,845		846		2,174		137		42		214
Excess Pension Plan settlement	136		—		—		—		—		—
Net periodic benefit cost (income)	$	4,819	$	5,803	$	7,145	$	(80)	$	(219)	$	2

We amortize prior service costs and credits on a straight-line basis over the average remaining service period of employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of prior service credit” in table above). We amortize the actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation or market-related value of plan assets (smoothed asset value) over the average remaining service period of active employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of net actuarial loss” in table above).

The service cost component of net periodic benefit cost (income) is reported in “General and administrative expenses” and “Operating expenses” on the consolidated statements of (loss) income, and the remaining components of net periodic benefit cost (income) are reported in “Other (expense) income, net.”

Adjustments to other comprehensive (loss) income related to our Pension Plans and other postretirement benefit plans were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
	(Thousands of Dollars)
Net unrecognized (loss) gain arising during the year:
Net actuarial (loss) gain	$	(2,159)	$	2,545	$	1,049	$	(793)	$	(1,559)	$	2,267

Net (gain) loss reclassified into income:
Amortization of prior service credit	(2,057)		(2,057)		(2,057)		(1,145)		(1,145)		(1,145)
Amortization of net actuarial loss	1,845		846		2,174		137		42		214
Net (gain) loss reclassified into income	(212)		(1,211)		117		(1,008)		(1,103)		(931)

Reclassification of stranded tax effects	—		—		(74)		—		—		—
Income tax benefit (expense)	28		14		(69)		—		—		(25)
Total changes to other comprehensive (loss) income	$	(2,343)	$	1,348	$	1,023	$	(1,801)	$	(2,662)	$	1,311

The amounts recorded as a component of “Accumulated other comprehensive loss” on the consolidated balance sheets related to our Pension Plans and other postretirement benefit plans were as follows:


	Pension Plans				Other Postretirement Benefit Plans
	December 31,				December 31,
	2020		2019		2020		2019
	(Thousands of Dollars)
Unrecognized actuarial loss	$	(24,878)	$	(24,564)	$	(3,846)	$	(3,190)
Prior service credit	10,433		12,490		6,029		7,174
Deferred tax asset	118		90		—		—
Accumulated other comprehensive (loss) income, net of tax	$	(14,327)	$	(11,984)	$	2,183	$	3,984

Investment Policies and Strategies

The investment policies and strategies for the assets of our qualified Pension Plan incorporate a well-diversified approach that is expected to earn long-term returns from capital appreciation and a growing stream of current income. This approach recognizes that assets are exposed to risk, and the market value of the Pension Plan’s assets may fluctuate from year to year. Risk tolerance is determined based on our financial ability to withstand risk within the investment program and the willingness to accept return volatility. In line with the investment return objective and risk parameters, the Pension Plan’s mix of assets includes a diversified portfolio of equity and fixed-income instruments. The aggregate asset allocation is reviewed on an annual basis. As of December 31, 2020, the target allocations for plan assets were 65% equity securities and 35% fixed income investments, with certain fluctuations permitted.

The overall expected long-term rate of return on plan assets for the Pension Plan is estimated using various models of asset returns. Model assumptions are derived using historical data with the assumption that capital markets are informationally efficient. Three models are used to derive the long-term expected returns for each asset class. Since each method has distinct advantages and disadvantages and differing results, an equal weighted average of the methods’ results is used.

Fair Value of Plan Assets

We disclose the fair value for each major class of plan assets in the Pension Plan in three levels: Level 1, defined as observable inputs such as quoted prices for identical assets or liabilities in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets that are not active; and Level 3, defined as unobservable inputs for which little or no market data exists.

The major classes of plan assets measured at fair value for the Pension Plan were as follows:


	December 31, 2020
	Level 1		Level 2		Level 3		Total
	(Thousands of Dollars)
Cash equivalent securities	$	2,125	$	—	$	—	$	2,125
Equity securities:
U.S. large cap equity fund (a)	—		104,857		—		104,857
International stock index fund (b)	20,732		—		—		20,732
Fixed income securities:
Bond market index fund (c)	55,013		—		—		55,013
Total	$	77,870	$	104,857	$	—	$	182,727


	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(Thousands of Dollars)
Cash equivalent securities	$	160	$	—	$	—	$	160
Equity securities:
U.S. large cap equity fund (a)	—		92,737		—		92,737
International stock index fund (b)	17,473		—		—		17,473
Fixed income securities:
Bond market index fund (c)	48,666		—		—		48,666
Total	$	66,299	$	92,737	$	—	$	159,036

(a)This fund is a low-cost equity index fund not actively managed that tracks the S&P 500. Fair values were estimated using pricing models, quoted prices of securities with similar characteristics or discounted cash flows.

(b)This fund tracks the performance of the Total International Composite Index.

(c)This fund tracks the performance of the Barclays Capital U.S. Aggregate Bond Index.

Contributions to the Pension Plans

For the year ended December 31, 2020, we contributed $11.5 million and $0.2 million to the Pension Plans and other postretirement benefit plans, respectively. During 2021, we expect to contribute approximately $9.4 million and $0.3 million to the Pension Plans and other postretirement benefit plans, respectively, which principally represent contributions either required by regulations or laws, or with respect to unfunded plans, necessary to fund current benefits.

Estimated Future Benefit Payments

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid for the years ending December 31:


	Pension Plans		Other Postretirement Benefit Plans
	(Thousands of Dollars)
2021	$	9,771	$	352
2022	$	10,030	$	397
2023	$	10,329	$	451
2024	$	10,846	$	483
2025	$	11,558	$	529
2026-2030	$	61,321	$	3,355

Assumptions

The weighted-average assumptions used to determine the benefit obligations were as follows:


	Pension Plans				Other Postretirement Benefit Plans
	December 31,				December 31,
	2020		2019		2020		2019
Discount rate	2.84	%	3.34	%	2.83	%	3.43	%
Rate of compensation increase	3.51	%	3.51	%	n/a		n/a
Cash balance interest crediting rate	2.00	%	2.00	%	n/a		n/a

The weighted-average assumptions used to determine the net periodic benefit cost (income) were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
Discount rate	3.34	%	4.40	%	3.72	%	3.43	%	4.53	%	3.82	%
Expected long-term rate of return on plan assets	6.50	%	6.50	%	6.50	%	n/a		n/a		n/a
Rate of compensation increase	3.51	%	3.51	%	3.51	%	n/a		n/a		n/a
Cash balance interest crediting rate	2.00	%	2.90	%	2.00	%	n/a		n/a		n/a

The assumed health care cost trend rates were as follows:


	December 31,
	2020		2019
Health care cost trend rate assumed for next year	6.84	%	6.84	%
Rate to which the cost trend rate was assumed to decrease (the ultimate trend rate)	5.00	%	5.00	%
Year that the rate reaches the ultimate trend rate	2028		2028

We sponsor a contributory postretirement health care plan for employees who retired prior to April 1, 2014. The plan has an annual limitation (a cap) on the increase of the employer’s share of the cost of covered benefits. The cap on the increase in employer’s cost is 2.5% per year.

- Definition

The entire disclosure for retirement benefits.

+ References

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+ Details

UNIT-BASED COMPENSATION

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

UNIT-BASED COMPENSATION

Overview

2019 LTIP. In April 2019, our common unitholders approved the 2019 Long-Term Incentive Plan (2019 LTIP) for eligible employees, consultants and directors of NuStar Energy L.P., and of NuStar GP, LLC, and their respective affiliates who perform services for us and our subsidiaries. The 2019 LTIP allows for the awarding of (i) options; (ii) restricted units; (iii) distribution equivalent rights (DERs); (iv) performance cash; (v) performance units; and (vi) unit awards. DERs entitle the participant to receive cash equal to cash distributions made on any award prior to its vesting. The 2019 LTIP permits the granting of awards totaling an aggregate of 2,500,000 common units, subject to adjustment as provided in the 2019 LTIP. The 2019 LTIP generally will be administered by the compensation committee of our board of directors. As of December 31, 2020, a total of 399,790 common units remained available to be awarded under the 2019 LTIP.

2000 LTIP. We sponsor the 2000 Long-Term Incentive Plan, as amended (2000 LTIP), which terminated with respect to new grants when the unitholders approved the 2019 LTIP. However, unvested restricted unit and performance unit awards granted under the 2000 LTIP remain outstanding.

2006 LTIP. Effective July 20, 2018 and in conjunction with the Merger, we assumed the 2006 Long-Term Incentive Plan, as amended (the 2006 LTIP). Prior to the Merger, Holdings sponsored the 2006 LTIP. At the effective time of the Merger, each outstanding award of Holdings restricted units was converted, on the same terms and conditions as were applicable to the awards immediately prior to the Merger, into an award of NuStar Energy restricted units. The number of NuStar Energy restricted units subject to the converted awards was determined pursuant to the 0.55 exchange ratio provided in the Merger agreement. The Holdings units remaining available to be awarded under the 2006 LTIP were also converted pursuant to the

exchange ratio provided in the Merger agreement. Effective with the approval of the 2019 LTIP, the 2006 LTIP terminated with respect to new grants; however, unvested restricted unit awards granted under the 2006 LTIP remain outstanding.

The following table summarizes information pertaining to all of our long-term incentive plans:


	Units Outstanding December 31,			Compensation Expense Year Ended December 31,
	2020	2019	2018	2020		2019		2018
				(Thousands of Dollars)
Restricted units:
Domestic employees	2,235,125	1,223,143	1,028,484	$	10,205	$	9,437	$	8,233
Non-employee directors (NEDs)	98,769	61,349	59,752	631		774		524
International employees	19,987	10,243	30,918	58		711		1,158
Performance awards	87,122	161,561	158,326	1,291		4,172		1,889

Unit awards	—	—	—	—		22,941		18,895
Total	2,441,003	1,456,296	1,277,480	$	12,185	$	38,035	$	30,699

Restricted Units

Our restricted unit awards are considered phantom units, as they represent the right to receive our common units upon vesting. We account for restricted units as either equity-classified awards or liability-classified awards, depending on expected method of settlement. Awards we settle with the issuance of common units upon vesting are equity-classified. Awards we settle in cash upon vesting are liability-classified. We record compensation expense ratably over the vesting period based on the fair value of the common units at the grant date (for domestic employees and NEDs) or the fair value of the common units measured at each reporting period (for international employees). DERs paid with respect to outstanding equity-classified unvested restricted units reduce equity, similar to cash distributions to unitholders, whereas DERs paid with respect to outstanding liability-classified unvested restricted units are expensed. In connection with the DERs for equity awards, we paid $2.1 million, $2.7 million and $2.0 million respectively, in cash, for the years ended December 31, 2020, 2019 and December 31, 2018.

Domestic Employees. The outstanding restricted units granted to domestic employees are equity-classified awards and generally vest over five years, beginning one year after the grant date. The fair value of these awards is measured at the grant date.

Non-Employee Directors. The outstanding restricted units granted to NEDs are equity-classified awards that vest over three years. On January 1, 2019 we adopted amended guidance that allows for the fair value of these awards to be measured at the grant date. The unvested restricted units granted to NEDs as of January 1, 2019 were measured at the fair value as of that date. Previously, the fair value of these awards was equal to the market price of our common units at each reporting period.

International Employees. The outstanding restricted units granted to international employees are cash-settled and accounted for as liability-classified awards. These awards vest over three years and the fair value is equal to the market price of our common units at each reporting period. For the year ended December 31, 2020, we granted 14,581 restricted units and 4,837 restricted units vested.

A summary of our equity-classified restricted unit awards is as follows:


	Measured at Grant Date Fair Value			Measured at Market Price
	Number of Units	Weighted-Average Fair Value Per Unit		Number of NEDs Units
Nonvested units as of January 1, 2018	736,746	$	35.95	27,097
Converted on July 20, 2018	53,447	24.99		18,915
Granted	518,282	24.07		34,303
Vested	(235,746)	35.12		(20,563)
Forfeited	(44,245)	36.05		—
Nonvested units as of December 31, 2018	1,028,484	29.47		59,752
Change in measurement (a)	59,752	20.93		(59,752)
Granted	596,881	26.46		—
Vested	(328,386)	30.11		—
Forfeited	(72,239)	28.05		—
Nonvested units as of December 31, 2019	1,284,492	27.48		—
Granted	1,454,998	12.10		—
Vested	(374,847)	28.47		—
Forfeited	(30,749)	26.75		—
Nonvested units as of December 31, 2020	2,333,894	17.70		—

(a) On January 1, 2019 we adopted amended guidance that allows for the fair value of these awards to be measured at the grant date. The unvested restricted units granted to NEDs as of January 1, 2019 were measured at the fair value as of that date.

The total fair value of our equity-classified restricted unit awards vested for the years ended December 31, 2020, 2019 and 2018 was $4.6 million, $9.3 million and $6.2 million, respectively. We issued 275,146, 242,199 and 189,399 common units in connection with these award vestings, net of employee tax withholding requirements, for the years ended December 31, 2020, 2019 and 2018, respectively. Unrecognized compensation cost related to our equity-classified employee awards totaled $38.1 million as of December 31, 2020, which we expect to recognize over a weighted-average period of 3.8 years.

Performance Awards

Performance awards are issued to certain of our key employees and represent either rights to receive our common units or cash upon achieving performance measures for the performance period established by the NuStar GP, LLC Compensation Committee. Achievement of the performance measures determines the rate at which the performance awards convert into our common units or cash, which ranges from zero to 200% for certain awards.

Performance awards vest in three annual increments (tranches), based upon our achievement of the performance measures set by the Compensation Committee during the performance periods that end on December 31 of each applicable year. Therefore, the performance awards are not considered granted for accounting purposes until the Compensation Committee has set the performance measures for each tranche of awards. Performance unit awards are equity-classified awards measured at the grant date fair value. In addition, since the performance unit awards granted do not receive DERs, the grant date fair value of these awards is reduced by the per unit distributions expected to be paid to common unitholders during the vesting period. Performance cash awards are accounted for as a liability but may be settled in common units. We record compensation expense ratably for each vesting tranche over its requisite service period (one year) if it is probable that the specified performance measures will be achieved. Additionally, changes in the actual or estimated outcomes that affect the quantity of performance awards expected to be converted into common units or paid in cash, are recognized as a cumulative adjustment. Performance units vested relate to the performance for the performance period ended December 31 of the previous year.

A summary of our performance unit awards is shown below:


		Granted for Accounting Purposes
	Total Performance Unit Awards	Performance Unit Awards	Weighted-Average Grant Date Fair Value per Unit
Outstanding as of January 1, 2018	80,961	38,865	$	50.04
Granted	116,230	80,690	23.43


Forfeitures	(38,865)	(38,865)	50.04
Outstanding as of December 31, 2018	158,326	80,690	23.43
Granted	95,969	74,439	28.01
Vested	(80,690)	(80,690)	23.43
Forfeitures	(12,044)	—	—
Outstanding as of December 31, 2019	161,561	74,439	28.01
Granted	—	57,448	13.21
Performance adjustment (a)	72,951	72,951	28.01
Vested	(147,390)	(147,390)	28.01

Outstanding as of December 31, 2020	87,122	57,448	13.21

(a) Common units granted and issued upon vesting of performance units earned at 198% of target related to the performance awards granted in 2019 and 2018.

The total fair value of our performance unit awards vested for the years ended December 31, 2020 and 2019 was $4.2 million and $2.1 million, respectively. For the years ended December 31, 2020 and 2019, we issued 93,440 and 50,054 common units in connection with these award vestings, net of employee tax withholding requirements, respectively, that relate to the performance periods ended December 31 of each previous year. For the year ended December 31, 2018, no performance units vested with respect to the performance period ended December 31, 2017.

For the year ended December 31, 2020, performance cash awards of $2.2 million were granted that vest in three annual tranches. On February 1, 2021, we settled the first tranche of the performance cash awards in common units, and together with the performance unit awards, we issued 58,070 common units, net of employee tax withholding requirements.

Unit Awards

Unit awards are equity-classified awards of fully vested common units. We accrued compensation expense in 2019 and 2018 that was paid in unit awards in the first quarter of the subsequent year. We base the number of unit awards granted on the fair value of the common units at the grant date. A summary of our unit awards is shown below:


Date of Grant	Grant Date Fair Value		Unit Awards Granted	Common Units Issued, Net of Employee Withholding Tax
	(Thousands of Dollars)
February and March 2020	$	22,941	834,224	571,735
February 2019	$	17,537	704,886	482,971
July 2018	$	1,358	55,133	35,745

INCOME TAXES

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

INCOME TAXES

Components of income tax expense related to certain of our continuing operations conducted through separate taxable wholly owned corporate subsidiaries were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Current:
U.S.	$	36	$	3,741	$	4,515
Foreign	2,415		1,489		4,658
Foreign withholding tax	—		101		192
Total current	2,451		5,331		9,365

Deferred:
U.S.	300		(490)		1,403
Foreign	(621)		(168)		394
Foreign withholding tax	533		182		246
Total deferred	212		(476)		2,043

Less: amounts reported in discontinued operations	—		101		1,251

Income tax expense	$	2,663	$	4,754	$	10,157

The difference between income tax expense recorded in our consolidated statements of (loss) income and income taxes computed by applying the applicable statutory federal income tax rate to income before income tax expense is due to the fact that the majority of our income is not subject to federal income tax due to our status as a limited partnership. We record a tax provision related to the amount of undistributed earnings of our foreign subsidiaries expected to be repatriated.

The tax effects of significant temporary differences representing deferred income tax assets and liabilities were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Deferred income tax assets:
Net operating losses	$	18,459	$	26,081
Employee benefits	134		372
Environmental and legal reserves	105		267

Capital loss	10,813		3,870
Other	834		693
Total deferred income tax assets	30,345		31,283
Less: Valuation allowance	(28,211)		(17,743)
Net deferred income tax assets	2,134		13,540

Deferred income tax liabilities:
Property, plant and equipment	(13,772)		(25,169)
Foreign withholding tax	(1,002)		(433)
Other	(371)		(365)
Total deferred income tax liabilities	(15,145)		(25,967)

Net deferred income tax liability	$	(13,011)	$	(12,427)

As of December 31, 2020, our U.S. and foreign corporate operations have net operating loss carryforwards for tax purposes totaling $58.0 million and $21.0 million, respectively, which are subject to various limitations on use and expire in years 2025 through 2037 for U.S. losses and in years 2019 through 2029 for foreign losses. However, U.S. losses generated after December 31, 2017, totaling $4.9 million, can be carried forward indefinitely. As of December 31, 2020, our U.S. corporate operations have a capital loss carryforward for tax purposes totaling $51.5 million, of which $17.7 million is subject to limitations on use and expires in 2024, and the remaining amount expires in 2025.

As of December 31, 2020 and 2019, we have a valuation allowance of $28.2 million and $17.7 million, respectively, related to our deferred tax assets on net operating losses and capital losses. We estimate the amount of valuation allowance based upon our expectations of taxable income in the various jurisdictions in which we operate and the period over which we can utilize those future deductions. The valuation allowance reflects uncertainties related to our ability to utilize certain net operating loss carryforwards before they expire. In 2020, there was a $10.0 million increase in the valuation allowance for the U.S. net operating loss and a $0.5 million increase in the foreign net operating loss valuation allowance due to the Texas City Sale and changes in our estimates of the amount of loss carryforwards that will be realized, based upon future taxable income.

The realization of net deferred income tax assets recorded as of December 31, 2020 is dependent upon our ability to generate future taxable income in the United States. We believe it is more likely than not that the net deferred income tax assets as of December 31, 2020 will be realized, based on expected future taxable income.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

SEGMENT INFORMATION

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

SEGMENT INFORMATION

Our reportable business segments consist of the pipeline, storage and fuels marketing segments. Our segments represent strategic business units that offer different services and products. We evaluate the performance of each segment based on its respective operating income, before general and administrative expenses and certain non-segmental depreciation and amortization expense. General and administrative expenses are not allocated to the operating segments since those expenses relate primarily to the overall management at the entity level. Our principal operations include the transportation of petroleum products and anhydrous ammonia, and the terminalling, storage and marketing of petroleum products. Intersegment revenues result from storage agreements with wholly owned subsidiaries of NuStar Energy at rates consistent with the rates charged to third parties for storage.

Results of operations for the reportable segments were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Revenues:
Pipeline	$	718,823	$	701,830	$	611,065

Storage:
Third parties	494,396		453,976		443,546
Intersegment	46		25		42
Total storage	494,442		454,001		443,588

Fuels marketing	268,345		342,215		465,651
Consolidation and intersegment eliminations	(46)		(25)		(42)
Total revenues	$	1,481,564	$	1,498,021	$	1,520,262

Depreciation and amortization expense:
Pipeline	$	177,384	$	166,991	$	153,943
Storage	99,092		97,573		93,345

Total segment depreciation and amortization expense	276,476		264,564		247,288
Other depreciation and amortization expense	8,625		8,360		8,604
Total depreciation and amortization expense	$	285,101	$	272,924	$	255,892

Operating income:
Pipeline	$	118,429	$	332,480	$	272,695
Storage	189,781		154,105		155,708
Fuels marketing	12,233		20,578		15,964
Consolidation and intersegment eliminations	—		(32)		32
Total segment operating income	320,443		507,131		444,399
General and administrative expenses	102,716		107,855		100,067
Other depreciation and amortization expense	8,625		8,360		8,604


Total operating income	$	209,102	$	390,916	$	335,728

Revenues by geographic area are shown in the table below:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
United States	$	1,441,892	$	1,465,135	$	1,481,844
Foreign	39,672		32,886		38,418
Consolidated revenues	$	1,481,564	$	1,498,021	$	1,520,262

For the years ended December 31, 2020, 2019 and 2018, Valero Energy Corporation accounted for approximately 20%, or $295.1 million, 21%, or $307.2 million, and 20%, or $303.7 million, of our revenues, respectively. These revenues were included in all of our reportable business segments. No other single customer accounted for 10% or more of our consolidated revenues.

Total amounts of property, plant and equipment, net by geographic area were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
United States	$	3,837,550	$	4,000,647
Foreign	119,962		118,332
Consolidated property, plant and equipment, net	$	3,957,512	$	4,118,979

Total assets by reportable segment were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Pipeline	$	3,609,508	$	3,884,819
Storage	1,897,167		2,082,832
Fuels marketing	31,967		31,064
Total segment assets	5,538,642		5,998,715

Other partnership assets	278,376		187,277
Total consolidated assets	$	5,817,018	$	6,185,992

Capital expenditures, including acquisitions, by reportable segment were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Pipeline	$	122,512	$	387,702	$	288,035
Storage	71,788		141,972		202,782

Other partnership assets	3,779		3,894		4,137
Total capital expenditures	$	198,079	$	533,568	$	494,954

Capital expenditures have not been adjusted to separately disclose those capital expenditures related to discontinued operations, which are included in the storage segment totaling $28.0 million and $114.8 million for the years ended December 31, 2019 and 2018, respectively.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2020
Accounting Policies [Abstract]
Consolidation	Consolidation The accompanying consolidated financial statements represent the consolidated operations of the Partnership and our subsidiaries. Inter-partnership balances and transactions have been eliminated in consolidation. The operations of certain pipelines and terminals in which we own an undivided interest are proportionately consolidated in the accompanying consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. On an ongoing basis, management reviews its estimates based on currently available information. Management may revise estimates due to changes in facts and circumstances.
Cash and Cash Equivalents	Cash and Cash EquivalentsCash equivalents are all highly liquid investments with an original maturity of three months or less when acquired.
Accounts Receivable	Accounts Receivable On January 1, 2020, we adopted new guidance from the Financial Accounting Standards Board (FASB) on credit losses, as discussed in Note 3. Trade receivables are carried at amortized cost, net of a valuation allowance for current expected credit losses. We extend credit to certain customers after review of various credit indicators, including the customer’s credit rating, and obtain letters of credit, guarantees or collateral as deemed necessary. We monitor our ongoing credit exposure through active review of customer balances against contract terms and due dates and pool customer receivables based upon days outstanding, which is our primary credit risk indicator. Our review activities include timely account reconciliations, dispute resolution and payment confirmations. Prior to adoption of the new guidance, outstanding customer receivable balances were regularly reviewed for possible non-payment indicators and allowances for doubtful accounts were recorded based upon management’s estimate of collectability at the time of its review.
Inventories	Inventories Inventories consist of petroleum products, materials and supplies. Inventories are valued at the lower of cost or net realizable value. Cost is determined using the weighted-average cost method. Our inventory, other than materials and supplies, consists of one end-product category, petroleum products, which we include in the fuels marketing segment. Accordingly, we determine lower of cost or net realizable value adjustments on an aggregate basis. Materials and supplies are valued at the lower of average cost or net realizable value.
Restricted Cash	Restricted Cash As of December 31, 2020 and 2019, we have restricted cash representing legally restricted funds that are unavailable for general use totaling $8.8 million, which is included in “Other long-term assets, net” on the consolidated balance sheet.
Property, Plant and Equipment	Property, Plant and Equipment We record additions to property, plant and equipment, including reliability and strategic capital expenditures, at cost. Repair and maintenance costs associated with existing assets that are minor in nature and do not extend the useful life of existing assets are charged to operating expenses as incurred. Depreciation of property, plant and equipment is recorded on a straight-line basis over the estimated useful lives of the related assets. When property or equipment is retired, sold or otherwise disposed of, the difference between the carrying value and the net proceeds is recognized in “Other (expense) income, net” or “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income in the year of disposition. We capitalize overhead costs and interest costs incurred on funds used to construct property, plant and equipment while the asset is under construction. The overhead costs and capitalized interest are recorded as part of the asset to which they relate and are amortized over the asset’s estimated useful life as a component of depreciation expense.
Goodwill	Goodwill We assess goodwill for impairment annually on October 1, or more frequently if events or changes in circumstances indicate it might be impaired. We have the option to first assess qualitative factors to determine whether it is necessary to perform a quantitative goodwill impairment test. We elected to bypass the qualitative assessment for all reporting units as of October 1, 2020 and performed a quantitative assessment. We performed a qualitative assessment as of October 1, 2019 and determined that goodwill was not impaired. We adopted amended accounting guidance in the first quarter of 2019 to measure goodwill impairment as the excess of each reporting unit’s carrying value over its fair value, not to exceed the carrying amount of goodwill for that reporting unit. The carrying value of each reporting unit equals the total identified assets (including goodwill) less the sum of each reporting unit’s identified liabilities. We used reasonable and supportable methods to assign the assets and liabilities to the appropriate reporting units in a consistent manner. As of December 31, 2020 and 2019, our reporting units to which goodwill has been allocated consisted of the following: •crude oil pipelines; •refined product pipelines; and •terminals, excluding our Point Tupper facility and our refinery crude storage tanks. As discussed in Note 11, in the first quarter of 2020, we recognized a goodwill impairment charge of $225.0 million associated with the crude oil pipelines reporting unit. In the first quarter of 2019, we recognized a goodwill impairment charge of $31.1 million for the goodwill associated with the Statia Bunkering reporting unit, which consisted of our bunkering operations at the St. Eustatius terminal facility. We recognize an impairment of goodwill if the carrying value of a reporting unit that contains goodwill exceeds its estimated fair value. In order to estimate the fair value of the reporting unit, including goodwill, management must make certain estimates and assumptions that affect the total fair value of the reporting unit including, among other things, an assessment of market conditions, projected cash flows, discount rates and growth rates. Management’s estimates of projected cash flows related to the reporting unit include, but are not limited to, future earnings of the reporting unit, assumptions about the use or disposition of the asset, estimated remaining life of the asset, and future expenditures necessary to maintain the asset’s existing service potential. We calculate the estimated fair value of each of our reporting units using a weighted-average of values calculated using an income approach and a market approach. The income approach involves estimating the fair value of each reporting unit by discounting its estimated future cash flows using a discount rate that would be consistent with a market participant’s assumption. The market approach bases the fair value measurement on information obtained from observed stock prices of public companies and recent merger and acquisition transaction data of comparable entities. Although we determined that no impairment charges resulted from our October 1, 2020 impairment assessment, the fair value of the crude oil pipelines reporting unit, which is included in the pipeline reporting segment, exceeded its carrying value by approximately 4%. The goodwill associated with the crude oil pipelines reporting unit totaled $308.6 million as of December 31, 2020. Our estimate of the fair value of the crude oil pipelines reporting unit is sensitive to typical valuation assumptions, particularly our estimates for the weighted-average cost of capital (WACC) used for the income approach and the guideline public company (GPC) multiple used for the market approach. Considering that the carrying value of the reporting unit was written down to its fair value with the first quarter of 2020 impairment charge, as further discussed in Note 11, changes to the WACC or GPC multiple used in our estimate could cause the fair value to be less than the carrying value of the crude oil pipelines reporting unit, resulting in an impairment. The fair values of the refined product pipelines and terminals reporting units substantially exceed their carrying values. Management’s estimates are based on numerous assumptions about future operations and market conditions, which we believe to be reasonable but are inherently uncertain. The uncertainties underlying our assumptions and estimates could differ significantly from actual results, including with respect to the duration and severity of the COVID-19 pandemic, the extent of travel restrictions, business closures and other efforts to control the spread of COVID-19 and the impact of actions by OPEC+, which could lead to a different determination of the fair value of our assets. We will continue to monitor the business and consider additional interim analysis of goodwill as appropriate.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We review long-lived assets, including property, plant and equipment, for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. We evaluate recoverability using undiscounted estimated net cash flows generated by the related asset or asset group. If the results of that evaluation indicate that the undiscounted cash flows are less than the carrying amount of the asset (i.e., the asset is not recoverable) we perform an impairment analysis. If our intent is to hold the asset for continued use, we determine the amount of impairment as the amount by which the net carrying value exceeds its fair value. If our intent is to sell the asset, and the criteria required to classify an asset as held for sale are met, we determine the amount of impairment as the amount by which the net carrying amount exceeds its fair value less costs to sell. As discussed in Note 4, we recognized long-lived asset impairment charges of $305.7 million in 2019 related to the St. Eustatius terminal facility. We believe that the carrying amounts of our long-lived assets as of December 31, 2020 are recoverable.
Income Taxes	Income Taxes We are a limited partnership and generally are not subject to federal or state income taxes. Accordingly, our taxable income or loss, which may vary substantially from income or loss reported for financial reporting purposes, is generally included in the federal and state income tax returns of our partners. For transfers of publicly held common units subsequent to our initial public offering, we have made an election permitted by Section 754 of the Internal Revenue Code (the Code) to adjust the common unit purchaser’s tax basis in our underlying assets to reflect the purchase price of the units. This results in an allocation of taxable income and expenses to the purchaser of the common units, including depreciation deductions and gains and losses on sales of assets, based upon the new unitholder’s purchase price for the common units. We conduct certain of our operations through taxable wholly owned corporate subsidiaries. We account for income taxes related to our taxable subsidiaries using the asset and liability method. Under this method, we recognize deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. We measure deferred taxes using enacted tax rates expected to apply to taxable income in the year those temporary differences are expected to be recovered or settled. We recognize a tax position if it is more likely than not that the tax position will be sustained, based on the technical merits of the position, upon examination. We record uncertain tax positions in the financial statements at the largest amount of benefit that is more likely than not to be realized. We had no unrecognized tax benefits as of December 31, 2020 and 2019. NuStar Energy and certain of its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. For U.S. federal and state purposes, as well as for our major non-U.S. jurisdictions, tax years subject to examination are 2016 through 2019, according to standard statute of limitations.
Asset Retirement Obligations	Asset Retirement Obligations We record a liability for asset retirement obligations at the fair value of the estimated costs to retire a tangible long-lived asset at the time we incur that liability, which is generally when the asset is purchased, constructed or leased, when we have a legal obligation to incur costs to retire the asset and when a reasonable estimate of the fair value of the obligation can be made. If a reasonable estimate cannot be made at the time the liability is incurred, we record the liability when sufficient information is available to estimate the fair value. We have asset retirement obligations with respect to certain of our assets due to various legal obligations to clean and/or dispose of those assets at the time they are retired. However, these assets can be used for an extended and indeterminate period of time as long as they are properly maintained and/or upgraded. It is our practice and current intent to maintain our assets and continue making improvements to those assets based on technological advances. As a result, we believe that our assets have indeterminate lives for purposes of estimating asset retirement obligations because dates or ranges of dates upon which we would retire these assets cannot reasonably be estimated at this time. When a date or range of dates can reasonably be estimated for the retirement of any asset, we estimate the costs of performing the retirement activities and record a liability for the fair value of these costs. We also have legal obligations in the form of leases and right-of-way agreements, which require us to remove certain of our assets upon termination of the agreement. However, these lease or right-of-way agreements generally contain automatic renewal provisions that extend our rights indefinitely or we have other legal means available to extend our rights. Liabilities for conditional asset retirement obligations related to the retirement of terminal assets with lease and right-of-way agreements were not material as of December 31, 2020 and 2019.
Environmental Remediation Costs	Environmental Remediation Costs Environmental remediation costs are expensed and an associated accrual established when site restoration and environmental remediation and cleanup obligations are either known or considered probable and can be reasonably estimated. These environmental obligations are based on estimates of probable undiscounted future costs using currently available technology and applying current regulations, as well as our own internal environmental policies. The environmental liabilities have not been reduced by possible recoveries from third parties. Environmental costs include initial site surveys, costs for remediation and restoration and ongoing monitoring costs, as well as fines, damages and other costs, when applicable and estimable. Adjustments to initial estimates are recorded, from time to time, to reflect changing circumstances and estimates based upon additional information developed in subsequent periods.
Revenue Recognition	Revenue Recognition Revenue-Generating Activities. Revenues for the pipeline segment are derived from interstate and intrastate pipeline transportation of refined products, crude oil and anhydrous ammonia and the applicable pipeline tariff. Revenues for the storage segment include fees for tank storage agreements, whereby a customer agrees to pay for a certain amount of storage in a tank over a period of time (storage terminal revenues), and throughput agreements, whereby a customer pays a fee per barrel for volumes moving through our terminals (throughput terminal revenues). Our terminals also provide blending, additive injections, handling and filtering services for which we charge additional fees, and certain of our facilities charge fees to provide marine services such as pilotage, tug assistance, line handling, launch service, emergency response services and other ship services (all of which are considered optional services). Revenues for the fuels marketing segment are derived from the sale of petroleum products. Within our pipeline and storage segments, we provide services on uninterruptible and interruptible bases. Uninterruptible services within our pipeline segment typically result from contracts that contain take-or-pay minimum volume commitments (MVCs) from the customer. Contracts with MVCs obligate the customer to pay for that minimum amount. If a customer fails to meet its MVC for the applicable service period, the customer is obligated to pay a deficiency fee based upon the shortfall between the actual volumes transported or stored and the MVC for that service period (deficiency payments). In exchange, those contracts with MVCs obligate us to stand ready to transport volumes up to the customer’s MVC. Within our storage segment, uninterruptible services arise from contracts containing a fixed monthly fee for the portion of storage capacity reserved by the customer. These contracts require that the customer pay the fixed monthly fee, regardless of whether or not it uses our storage facility (i.e., take-or-pay obligation), and that we stand ready to store that volume. Interruptible services within our pipeline and storage segments are generally provided when and to the extent we determine the requested capacity is available. The customer typically pays a per-unit rate for the actual quantities of services it receives. For the majority of our contracts, we recognize revenue in the amount to which we have a right to invoice. Generally, payment terms do not exceed 30 days. Performance Obligations. The majority of our contracts contain a single performance obligation. For our pipeline segment, the single performance obligation encompasses multiple activities necessary to deliver our customers’ products to their destinations. Typically, we satisfy this performance obligation over time as the product volume is delivered in or out of the pipelines. Certain of our pipeline segment customer contracts include an incentive pricing structure, which provides a discounted rate for the remainder of the contract once the customer exceeds a cumulative volume. The ability to receive discounted future services represents a material right to the customer, which results in a second performance obligation in those contracts. The performance obligation for our storage segment consists of multiple activities necessary to receive, store and deliver our customers’ products. We typically satisfy this performance obligation over time as the product volume is delivered in or out of the tanks (for throughput terminal revenues) or with the passage of time (for storage terminal revenues). Product sales contracts associated with our fuels marketing segment generally include a single performance obligation to deliver specified volumes of a commodity, which we satisfy at a point in time, when the product is delivered and the customer obtains control of the commodity. Optional services described in our contracts do not provide a material right to the customer, and are not considered a separate performance obligation in the contract. If and when a customer elects an optional service, and the terms of the contract are otherwise met, those services become part of the existing performance obligation. Transaction Price. For uninterruptible services, we determine the transaction price at contract inception based on the guaranteed minimum amount of revenue over the term of the contract. For interruptible services and optional services, we determine the transaction price based on our right to invoice the customer for the value of services provided to the customer for the applicable period. In certain instances, our customers reimburse us for capital projects, in arrangements referred to as contributions in aid of construction, or CIAC. Typically, in these instances, we receive upfront payments for future services, which are included in the transaction price of the underlying service contract. We collect taxes on certain revenue transactions to be remitted to governmental authorities, which may include sales, use, value-added and some excise taxes. These taxes are not included in the transaction price and are, therefore, excluded from revenues. Allocation of Transaction Price. We allocate the transaction price to the single performance obligation that exists in the vast majority of our contracts with customers. For the few contracts that have a second performance obligation, such as those that include an incentive pricing structure, we calculate an average rate based on the estimated total volumes to be delivered over the term of the contract and the resulting estimated total revenue to be billed using the applicable rates in the contract. We allocate the transaction price to the two performance obligations by applying the average rate to product volumes as they are delivered to the customer over the term of the contract. Determining the timing and amount of volumes subject to these incentive pricing contracts requires judgment that can impact the amount of revenue allocated to the two separate performance obligations. We base our estimates on our analysis of expected future production information available from our customers or other sources, which we update at least quarterly. Some of our MVC contracts include provisions that allow the customer to apply deficiency payments to future service periods (the carryforward period). In those instances, we have not satisfied our performance obligation as we still have the obligation to perform those services, subject to contractual and/or capacity constraints, at the customer’s request. At least quarterly, we assess the customer’s ability to utilize any deficiency payments during the carryforward period. If we receive a deficiency payment from a customer that we expect the customer to utilize during the carryforward period, we defer that amount as a contract liability. We will consider the performance obligation satisfied and allocate any deferred deficiency payments to our performance obligation when the customer utilizes the deficiency payment, the carryforward period ends or we determine the customer cannot or will not utilize the deficiency payment (i.e. breakage). If our contract does not allow the customer to apply deficiency payments to future service periods, we allocate the deficiency payment to the already satisfied portion of the performance obligation.
Income Allocation	Income Allocation Our partnership agreement contains provisions for the allocation of net income to the unitholders and, prior to the merger with our general partner, to the general partner. Our net income for each quarterly reporting period is first allocated to the preferred limited partner unitholders in an amount equal to the earned distributions for the respective reporting period and, prior to the merger, then to the general partner in an amount equal to the general partner’s incentive distribution calculated based upon the declared distribution for the respective reporting period. We allocate the remaining net income or loss among the common unitholders. Prior to the merger, we allocated the remaining net income or loss among the common unitholders (98%) and general partner (2%). See Note 5 for further discussion of the merger.
Basic and Diluted Net Income per Common Unit	Basic and Diluted Net (Loss) Income Per Common Unit Basic and diluted net (loss) income per common unit are determined pursuant to the two-class method. Under this method, all earnings are allocated to our limited partners and participating securities based on their respective rights to receive distributions earned during the period. Participating securities include restricted units awarded under our long-term incentive plans and, prior to the merger with our general partner, included our general partner’s interest. We compute basic net (loss) income per common unit by dividing net (loss) income attributable to our common limited partners by the weighted-average number of common units outstanding during the period. We compute diluted net (loss) income per common unit by dividing net (loss) income attributable to our common limited partners by the sum of (i) the weighted-average number of common units outstanding during the period and (ii) the effect of dilutive potential common units outstanding during the period. Dilutive potential common units include contingently issuable performance units awarded and the Series D Preferred Units. See Note 23 for additional information on our performance units, Note 18 for additional information on our Series D Preferred Units and Note 20 for the calculation of basic and diluted net (loss) income per common unit.
Derivative Financial Instruments	Derivative Financial Instruments When we apply hedge accounting, we formally document all relationships between hedging instruments and hedged items. This process includes identification of the hedging instrument and the hedged transaction, the nature of the risk being hedged and how the hedging instrument’s effectiveness will be assessed. To qualify for hedge accounting, at inception of the hedge we assess whether the derivative instruments that are used in our hedging transactions are expected to be highly effective in offsetting changes in cash flows. Throughout the designated hedge period and at least quarterly, we assess whether the derivative instruments are highly effective and continue to qualify for hedge accounting. We enter into the forward-starting swaps in order to hedge the risk of changes in the interest payments attributable to changes in the benchmark interest rate during the period from the effective date of the swap to the issuance of the forecasted debt. For forward-starting interest rate swaps designated and qualifying as cash flow hedges, we recognize the fair value of each interest rate swap in the consolidated balance sheets. We record changes in the fair value of the hedge as a component of accumulated other comprehensive income (loss) (AOCI), to the extent those cash flow hedges remain highly effective. If at any point a cash flow hedge ceases to qualify for hedge accounting, changes in the fair value of the hedge are recognized in “Interest expense, net” from that date forward. The amount accumulated in AOCI is amortized into “Interest expense, net” as the forecasted interest payments occur or if the interest payments are probable not to occur. We classify cash flows associated with our derivative instruments as operating cash flows in the consolidated statements of cash flows, except for receipts or payments associated with terminated forward-starting interest rate swap agreements, which are included in cash flows from financing activities. See Note 17 for additional information regarding our derivative financial instruments.
Unit-based Compensation	Unit-based Compensation Unit-based compensation for our long-term incentive plans is recorded in our consolidated balance sheets based on the fair value of the awards granted and recognized as compensation expense primarily on a straight-line basis over the requisite service period. Forfeitures of our unit-based compensation awards are recognized as an adjustment to compensation expense when they occur. Unit-based compensation expense is included in “General and administrative expenses” on our consolidated statements of (loss) income. Most of our currently outstanding awards are classified as equity awards as we intend to settle these awards through the issuance of our common units. See Note 23 for additional information regarding our unit-based compensation.
Foreign Currency Translation	Foreign Currency Translation The functional currencies of our foreign subsidiaries are the local currencies of the countries in which the subsidiaries are located. The assets and liabilities of our foreign subsidiaries with local functional currencies are translated to U.S. dollars at period-end exchange rates, and income and expense items are translated to U.S. dollars at weighted-average exchange rates in effect during the period. These translation adjustments are included in “Accumulated other comprehensive loss” in the equity section of the consolidated balance sheets. Gains and losses on foreign currency transactions are included in “Other (expense) income, net” or “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income.
Reclassifications	ReclassificationsWe have reclassified certain previously reported amounts in the consolidated financial statements and notes to conform to current-period presentation.

LEASE ASSETS AND LIABILITIES (Policies)	12 Months Ended
LEASE ASSETS AND LIABILITIES (Policies)	Dec. 31, 2020
Leases [Abstract]
Leases [Policy Text Block]	We elected the following practical expedients permitted under the transition guidance within the new standard: •the package of practical expedients, which, among other things, allowed us to carry forward historical lease classification; •the practical expedient specifically related to land easements, which, among other things, allowed us to carry forward our historical accounting treatment for existing land easement agreements; •the lessee practical expedient to combine lease and non-lease components for all of our asset classes except the other pipeline and terminal equipment asset class; and •the lessor practical expedient to combine lease and non-lease components and to account for the transaction based on the predominant component (i.e., ASC Topic 842 or ASC Topic 606, “Revenue from Contracts with Customers”). We apply this expedient to certain contracts in which we agree to provide both storage capacity and optional services to customers. We record all leases on our consolidated balance sheet except for those leases with an initial term of 12 months or less, which are expensed on a straight-line basis over the lease term. We use judgment in determining the reasonably certain lease term and consider factors such as the nature and utility of the leased asset, as well as the importance of the leased asset to our operations. We calculate the present value of our lease liabilities based upon our incremental borrowing rate unless the rate implicit in the lease is readily determinable.

DISPOSITIONS AND DISCONTINUED OPERATIONS (Tables)

12 Months Ended

Dec. 31, 2020

Discontinued Operations and Disposal Groups [Abstract]

Discontinued Operations, Supplemental Income Statement Disclosures [Table Text Block]

The following is a reconciliation of the major classes of line items included in “(Loss) income from discontinued operations, net of tax” on the consolidated statements of (loss) income:


	Year Ended December 31,
	2019		2018
	(Thousands of Dollars)



Revenues	$	248,981	$	441,495
Costs and expenses:





Cost of revenues	220,595		407,256
Impairment losses	336,838		—
General and administrative expenses (excluding depreciation and amortization expense)	1,231		6,133
Other depreciation and amortization expense	—		271
Total costs and expenses	558,664		413,660
Operating (loss) income	(309,683)		27,835
Interest income (expense), net	32		(1,839)
Other (expense) income, net	(2,775)		34,674
(Loss) income from discontinued operations before income tax expense	(312,426)		60,670
Income tax expense	101		1,251
(Loss) income from discontinued operations, net of tax	$	(312,527)	$	59,419

Discontinued Operations, Selected Cash Flow Information [Table Text Block]

The following table presents selected cash flow information associated with our discontinued operations:


	Year Ended December 31,
	2019		2018
	(Thousands of Dollars)
Capital expenditures	$	(27,954)	$	(114,811)

Significant noncash operating activities and other adjustments:
Depreciation and amortization expense	$	8,536	$	41,982
Asset impairment losses	$	305,715	$	—
Goodwill impairment loss	$	31,123	$	—
Loss from sale of the St. Eustatius Operations	$	3,942	$	—
Loss from sale of the European Operations	$	—	$	43,366
Gain from insurance recoveries	$	—	$	(78,756)

MERGER AND RELATED PARTY AGREEMENTS (Tables)

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Loss to common unitholders attributable to the Merger

The excess of (x) the fair value of the consideration transferred in exchange for the outstanding Holdings units over (y) the carrying value of the general partner interest in the Partnership was subtracted from net income available to common unitholders in the calculation of net loss per common unit attributable to the Merger as follows (in thousands of dollars, except unit and per unit data):


Consideration transferred:
Fair value of incremental NS common units issued	$	335,106
Holdings debt and assumed net current liabilities	52,075
Transaction costs	15,897
Total consideration	403,078

Carrying value of general partner interest	25,999
Loss to common unitholders attributable to the Merger	$	(377,079)

For the year ended December 31, 2018:
Basic weighted-average common units outstanding	99,490,495
Loss per common unit attributable to the Merger	$	(3.79)

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Contract with Customer, Asset and Liability [Table Text Block]

The following table provides information about contract assets and contract liabilities from contracts with customers:


	2020				2019				2018
	Contract Assets		Contract Liabilities		Contract Assets		Contract Liabilities		Contract Assets		Contract Liabilities
	(Thousands of Dollars)
Balances as of January 1:
Current portion	$	2,140	$	(21,083)	$	2,066	$	(21,579)	$	1,956	$	(13,801)
Noncurrent portion	1,003		(40,289)		539		(38,945)		171		(46,361)
Held for sale	—		—		—		(25,357)		—		(302)
Total	3,143		(61,372)		2,605		(85,881)		2,127		(60,464)

Activity:
Additions	5,686		(69,830)		4,890		(52,957)		3,281		(83,243)
Transfer to accounts receivable	(4,828)		—		(4,352)		—		(2,803)		—
Transfer to revenues, including amounts reported in discontinued operations	(375)		61,646		—		77,466		—		57,826

Total	483		(8,184)		538		24,509		478		(25,417)

Balances as of December 31:
Current portion	2,694		(22,019)		2,140		(21,083)		2,066		(21,579)
Noncurrent portion	932		(47,537)		1,003		(40,289)		539		(38,945)
Held for sale	—		—		—		—		—		(25,357)
Total	$	3,626	$	(69,556)	$	3,143	$	(61,372)	$	2,605	$	(85,881)

Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]


2021	$	486,339
2022	354,666
2023	261,205
2024	184,862
2025	128,279
Thereafter	173,917
Total	$	1,589,268

Disaggregation of Revenue [Table Text Block]

The following table disaggregates our revenues:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Pipeline segment:
Crude oil pipelines	$	329,105	$	316,417	$	248,261
Refined products and ammonia pipelines (excluding lessor revenues)	387,793		376,588		362,750
Total pipeline segment revenues from contracts with customers	716,898		693,005		611,011
Lessor revenues	1,925		8,825		54
Total pipeline segment revenues	718,823		701,830		611,065

Storage segment:
Throughput terminals	136,632		114,243		83,157
Storage terminals (excluding lessor revenues)	316,496		298,984		320,582
Total storage segment revenues from contracts with customers	453,128		413,227		403,739
Lessor revenues	41,314		40,774		39,849
Total storage segment revenues	494,442		454,001		443,588

Fuels marketing segment:
Revenues from contracts with customers	268,345		342,215		465,651

Consolidation and intersegment eliminations	(46)		(25)		(42)

Total revenues	$	1,481,564	$	1,498,021	$	1,520,262

ALLOWANCE FOR CREDIT LOSSES (Tables)

12 Months Ended

Dec. 31, 2020

Allowance for Credit Loss [Abstract]

Allowance for Credit Losses [Table Text Block]

The balance of and changes in the allowance for credit losses consisted of the following:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Balance as of beginning of year	$	72	$	9,412	$	9,380
Current period provision for credit losses	441		2,322		233
Write-offs charged against the allowance	(513)		(11,662)		(201)


Balance as of end of year	$	—	$	72	$	9,412

INVENTORIES (Tables)

12 Months Ended

Dec. 31, 2020

Inventory Disclosure [Abstract]

Schedule of Inventory Table [Text Block]

Inventories consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Petroleum products	$	7,394	$	8,646
Materials and supplies	3,665		3,747
Total	$	11,059	$	12,393

PROPERTY, PLANT AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment [Table Text Block]

Property, plant and equipment consisted of the following:


	Estimated Useful Lives			December 31,
				2020		2019
	(Years)			(Thousands of Dollars)
Land, buildings and improvements	0	-	40	$	440,358	$	444,156
Pipelines, storage and terminals	15	-	40	5,253,507		5,162,426
Rights-of-way	20	-	40	359,441		350,026
Construction in progress		-		111,436		230,536
Total				6,164,742		6,187,144
Less accumulated depreciation and amortization				(2,207,230)		(2,068,165)
Property, plant and equipment, net				$	3,957,512	$	4,118,979

INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2020

Intangible Assets, Net (Excluding Goodwill) [Abstract]

Schedule of Finite-Lived Intangible Assets by Major Class [Table Text Block]

Intangible assets consisted of the following:


	Weighted-Average Amortization Period	December 31, 2020				December 31, 2019
		Cost		Accumulated Amortization		Cost		Accumulated Amortization
	(Years)	(Thousands of Dollars)
Customer contracts and relationships	18	$	863,900	$	(235,205)	$	863,900	$	(183,832)
Other	47	2,359		(845)		2,359		(795)
Total		$	866,259	$	(236,050)	$	866,259	$	(184,627)

GOODWILL (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill [Table Text Block]

The balances of and changes in the carrying amount of goodwill by segment were as follows:


	Pipeline		Storage		Total
	(Thousands of Dollars)


Balances as of January 1, 2019 and 2020	$	704,231	$	301,622	$	1,005,853





Activity for the year ended December 31, 2020:
Goodwill impairment loss on crude oil pipelines	(225,000)		—		(225,000)
Texas City Sale	—		(14,437)		(14,437)

Balances as of December 31, 2020:
Goodwill	704,231		287,185		991,416
Accumulated impairment loss	(225,000)		—		(225,000)
Net goodwill	$	479,231	$	287,185	$	766,416

ACCRUED LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2020

Accrued Liabilities, Current [Abstract]

Schedule of Accrued Liabilities [Table Text Block]

Accrued liabilities consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Employee wages and benefit costs	$	27,805	$	36,704
Revenue contract liabilities	22,019		21,083
Interest rate swaps	—		19,169
Operating lease liabilities	10,890		10,416

Environmental costs	5,371		4,837

Other	11,685		16,401
Accrued liabilities	$	77,770	$	108,610

DEBT (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Short-term Debt [Table Text Block]

Short-term debt consisted of the following:


	December 31,
	2020		2019
	(Thousands of Dollars)
Short-term line of credit	$	—	$	5,500
Current portion of finance leases (refer to Note 16)	$	3,839	$	4,546

Schedule of Long-term Debt Instruments [Table Text Block]

Long-term debt consisted of the following:


				December 31,
	Maturity			2020		2019
				(Thousands of Dollars)
Revolving Credit Agreement		2023		$	—	$	475,000
4.80% senior notes		2020		—		450,000
6.75% senior notes		2021		300,000		300,000
4.75% senior notes		2022		250,000		250,000
5.75% senior notes		2025		600,000		—
6.00% senior notes		2026		500,000		500,000
5.625% senior notes		2027		550,000		550,000
6.375% senior notes		2030		600,000		—
Subordinated Notes		2043		402,500		402,500
GoZone Bonds	2038	thru	2041	322,140		365,440
Receivables Financing Agreement		2023		57,000		62,200
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs		N/A		(42,382)		(23,301)
Total long-term debt (excluding finance leases)				3,539,258		3,331,839
Finance leases (refer to Note 16)				54,238		55,446
Less current portion				—		452,367
Long-term debt, less current portion				$	3,593,496	$	2,934,918

Schedule of Maturities of Long-term Debt [Table Text Block]

The long-term debt repayments (excluding finance leases) are due as follows (in thousands of dollars):


2021	$	300,000
2022	250,000
2023	57,000
2024	—
2025	600,000
Thereafter	2,374,640
Total repayments	3,581,640
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	(42,382)
Total long-term debt (excluding finance leases)	$	3,539,258

Schedule of GoZone Bonds [Table Text Block]

The following table summarizes the GoZone Bonds outstanding as of December 31, 2020:

Series

Date Issued

Amount
Outstanding

Interest Rate

Mandatory
Purchase Date

Maturity Date

(Thousands of Dollars)

Series 2008

June 26, 2008

55,440

6.10

June 1, 2030

June 1, 2038

Series 2010

July 15, 2010

100,000

6.35

n/a

July 1, 2040

Series 2010A

October 7, 2010

43,300

6.35

n/a

October 1, 2040

Series 2010B

December 29, 2010

48,400

6.10

June 1, 2030

December 1, 2040

Series 2011

August 9, 2011

75,000

5.85

June 1, 2025

August 1, 2041

Total

322,140

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS (Tables)

12 Months Ended

Dec. 31, 2020

Environmental Remediation Obligations [Abstract]

Schedule of Environmental Accrual Rollforward [Table Text Block]

The balance of and changes in the accruals for environmental matters were as follows:


	Year Ended December 31,
	2020		2019
	(Thousands of Dollars)
Balance as of the beginning of year	$	7,938	$	7,753
Additions to accrual	3,692		3,700
Payments	(3,257)		(3,515)

Balance as of the end of year	$	8,373	$	7,938

Environmental Accruals By Balance Sheet Location [Table Text Block]

Accruals for environmental matters are included in the consolidated balance sheets as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Accrued liabilities	$	5,371	$	4,837
Other long-term liabilities	3,002		3,101
Accruals for environmental matters	$	8,373	$	7,938

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Payments for Operating Leases and Purchase Obligations [Table Text Block]

Future minimum rental payments applicable to all noncancellable purchase obligations as of December 31, 2020 are as follows:


	Payments Due by Period
	2021		2022		2023		2024		2025		There- after		Total
	(Thousands of Dollars)
Purchase obligations	$	9,980	$	7,647	$	2,039	$	1,025	$	483	$	4,520	$	25,694

LEASE ASSETS AND LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Schedule of Right-of-Use Assets and Lease Liabilities

Right-of-use assets and lease liabilities included in our consolidated balance sheet were as follows:


		December 31,
	Balance Sheet Location	2020		2019
		(Thousands of Dollars)
Right-of-Use Assets:
Operating	Other long-term assets, net	$	87,443	$	81,219
Finance	Property, plant and equipment, net of accumulated amortization of $8,444 and $3,748	$	73,319	$	74,953

Lease Liabilities:
Operating:
Current	Accrued liabilities	$	10,890	$	10,416
Noncurrent	Other long-term liabilities	74,899		70,083
Total operating lease liabilities		$	85,789	$	80,499
Finance:
Current	Current portion of debt and finance lease obligations	$	3,839	$	4,546
Noncurrent	Long-term debt, less current portion	54,238		55,446
Total finance lease liabilities		$	58,077	$	59,992

Maturity Analysis of Lease Liabilities

As of December 31, 2020, maturities of our operating and finance lease liabilities were as follows:


	Operating Leases		Finance Leases
	(Thousands of Dollars)
2021	$	13,137	$	5,907
2022	12,419		5,231
2023	11,170		5,102
2024	10,294		4,622
2025	8,154		3,898
Thereafter	53,288		56,079
Total lease payments	$	108,462	$	80,839
Less: Interest	22,673		22,762
Present value of lease liabilities	$	85,789	$	58,077

Lease Cost

Costs incurred for leases, including costs associated with discontinued operations, were as follows:


	Year Ended December 31,
	2020		2019
	(Thousands of Dollars)
Operating lease cost	$	16,814	$	29,167
Finance lease cost:
Amortization of right-of-use assets	$	4,700	$	3,748
Interest expense on lease liability	$	2,201	$	2,212
Short-term lease cost	$	15,359	$	19,140
Variable lease cost	$	8,653	$	6,990
Total lease cost	$	47,727	$	61,257

Additional Lease Information

The table below presents additional information regarding our leases as of and for the years ended December 31, 2020 and 2019:


	Year ended December 31,
	2020						2019
	Operating Leases			Finance Leases			Operating Leases			Finance Leases
	(Thousands of Dollars, Except Term and Rate Data)
Cash outflows from operating activities	$	14,487		$	2,208		$	27,567		$	2,027
Cash outflows from financing activities	$	—		$	4,981		$	—		$	3,700
Right-of-use assets obtained in exchange for lease liabilities	$	20,830		$	3,077		$	2,153		$	4,430
Weighted-average remaining lease term (in years)	13			19			15			20
Weighted-average discount rate	3.2		%	3.7		%	3.6		%	3.7		%

Assets Leased to Others


	Estimated Useful Life	December 31,
		2020		2019
	(Years)	(Thousands of Dollars)
Lease storage assets, at cost	30	$	241,664	238,204
Less accumulated depreciation		(130,217)		(121,545)
Lease storage assets, net		$	111,447	$	116,659

DERIVATIVES AND FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Value of Unwound Interest Rate Swap Agreements [Table Text Block]


		December 31,
Unwound Interest Rate Swap Agreements	Balance Sheet Location	2020		2019
		(Thousands of Dollars)
Fixed-to-floating	Current portion of long-term debt	$	—	$	2,755
Fixed-to-floating	Long-term debt, less current portion	$	1,363	$	2,568
Forward-starting	Accumulated other comprehensive (loss) income	$	(42,150)	$	3,045

Derivative Instruments, Gain (Loss) [Table Text Block]

Our forward-starting interest rate swaps had the following impact on earnings:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
(Loss) gain recognized in other comprehensive income (loss) on derivative	$	(30,291)	$	(19,045)	$	17,912
Loss reclassified from AOCI into interest expense, net	$	(4,265)	$	(3,814)	$	(5,499)

Fair Value and Carrying Value of Debt [Table Text Block]

The estimated fair values and carrying amounts of the long-term debt, including the current portion and excluding finance leases, were as follows:


	December 31, 2020		December 31, 2019
	(Thousands of Dollars)
Fair value	$	3,799,378	$	3,442,001
Carrying amount	$	3,539,258	$	3,331,839

PARTNERS' EQUITY (Tables)

12 Months Ended

Dec. 31, 2020

Distribution Made to Limited Partner [Line Items]

Schedule of Preferred Units [Table Text Block]


Units	Original Issuance Date	Number of Units Issued and Outstanding	Price per Unit		Fixed Distribution Rate per Annum (as a Percentage of the $25.00 Liquidation Preference per Unit)		Fixed Distribution Rate per Unit per Annum		Fixed Distribution per Annum (in thousands)		Optional Redemption Date/Date at Which Distribution Rate Becomes Floating	Floating Annual Rate (as a Percentage of the $25.00 Liquidation Preference per Unit)
Series A Preferred Units	November 25, 2016	9,060,000	$	25.00	8.50	%	$	2.125	$	19,252	December 15, 2021	Three-month LIBOR plus 6.766%
Series B Preferred Units	April 28, 2017	15,400,000	$	25.00	7.625	%	$	1.90625	$	29,357	June 15, 2022	Three-month LIBOR plus 5.643%
Series C Preferred Units	November 30, 2017	6,900,000	$	25.00	9.00	%	$	2.25	$	15,525	December 15, 2022	Three-month LIBOR plus 6.88%

Schedule of Common Units [Table Text Block]

The following table shows the balance of and changes in the number of our common units outstanding:


	Year Ended December 31,
	2020	2019	2018
Balance as of the beginning of year	108,527,806	107,225,156	93,176,683
Issuance of units	—	527,426	413,736
Unit-based compensation (refer to Note 23 for discussion)	940,321	775,224	225,144
Merger (refer to Note 5 for discussion)	—	—	13,409,593
Balance as of the end of year	109,468,127	108,527,806	107,225,156

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

The balance of and changes in the components included in AOCI were as follows:


	Foreign Currency Translation		Cash Flow Hedges		Pension and Other Postretirement Benefits		Total
	(Thousands of Dollars)
Balance as of January 1, 2018	$	(51,603)	$	(24,304)	$	(9,020)	$	(84,927)
Other comprehensive (loss) income before reclassification adjustments	(13,880)		17,912		3,282		7,314
Sale of European Operations reclassified into other income, net	18,124		—		—		18,124
Net gain on pension costs reclassified into other income, net	—		—		(814)		(814)
Net loss on cash flow hedges reclassified into interest expense, net	—		5,499		—		5,499
Other	60		—		(134)		(74)
Other comprehensive income	4,304		23,411		2,334		30,049
Balance as of December 31, 2018	(47,299)		(893)		(6,686)		(54,878)
Other comprehensive income (loss) before reclassification adjustments	3,527		(19,045)		1,000		(14,518)
Net gain on pension costs reclassified into other income, net	—		—		(2,314)		(2,314)
Net loss on cash flow hedges reclassified into interest expense, net	—		3,814		—		3,814

Other comprehensive income (loss)	3,527		(15,231)		(1,314)		(13,018)
Balance as of December 31, 2019	(43,772)		(16,124)		(8,000)		(67,896)
Other comprehensive income (loss) before reclassification adjustments	1,410		(30,291)		(2,924)		(31,805)
Net gain on pension costs reclassified into other income, net	—		—		(1,220)		(1,220)
Net loss on cash flow hedges reclassified into interest expense, net	—		4,265		—		4,265

Other comprehensive income (loss)	1,410		(26,026)		(4,144)		(28,760)
Balance as of December 31, 2020	$	(42,362)	$	(42,150)	$	(12,144)	$	(96,656)

Common Limited Partner [Member]

Distribution Made to Limited Partner [Line Items]

Distributions Made to Limited Partner, by Distribution [Table Text Block]

The following table summarizes information about cash distributions to our common limited partners applicable to the period in which the distributions were earned:


	Cash Distributions Per Unit		Total Cash Distributions		Record Date	Payment Date
			(Thousands of Dollars)
Quarter ended:
December 31, 2020	$	0.40	$	43,787	February 8, 2021	February 12, 2021
September 30, 2020	0.40		43,678		November 6, 2020	November 13, 2020
June 30, 2020	0.40		43,678		August 7, 2020	August 13, 2020
March 31, 2020	0.40		43,730		May 11, 2020	May 15, 2020
Year ended December 31, 2020	$	1.60	$	174,873

Year ended December 31, 2019	$	2.40	$	259,136
Year ended December 31, 2018	$	2.40	$	248,705

NET (LOSS) INCOME PER COMMON UNIT (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule of Net (Loss) Income Per Unit [Text Block]

The following table details the calculation of net loss per common unit:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars, Except Unit and Per Unit Data)
Net (loss) income	$	(198,983)	$	(105,693)	$	205,794
Distributions to preferred limited partners	(124,882)		(121,693)		(92,540)
Distributions to general partner	—		—		(1,141)
Distributions to common limited partners	(174,873)		(259,136)		(248,705)
Distribution equivalent rights to restricted units	(2,093)		(2,659)		(2,045)
Distributions in excess of (loss) income	$	(500,831)	$	(489,181)	$	(138,637)

Distributions to common limited partners	$	174,873	$	259,136	$	248,705
Allocation of distributions in excess of (loss) income	(500,831)		(489,181)		(138,659)
Series D Preferred Unit accretion (refer to Note 18)	(17,626)		(18,085)		(8,195)
Loss to common unitholders attributable to the Merger (refer to Note 5)	—		—		(377,079)
Net loss attributable to common units	$	(343,584)	$	(248,130)	$	(275,228)

Basic weighted-average common units outstanding	109,155,117		107,789,030		99,490,495

Diluted common units outstanding:
Basic weighted-average common units outstanding	109,155,117		107,789,030		99,490,495
Effect of dilutive potential common units	—		65,669		40,677
Diluted weighted-average common units outstanding	109,155,117		107,854,699		99,531,172

Basic and diluted net loss per common unit	$	(3.15)	$	(2.30)	$	(2.77)

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)

12 Months Ended

Dec. 31, 2020

Supplemental Cash Flow Information [Abstract]

Schedule of Changes in Current Assets and Liabilities [Table Text Block]

Changes in current assets and current liabilities were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Decrease (increase) in current assets:
Accounts receivable	$	14,589	$	(23,480)	$	22,482
Receivable from related party	—		—		160
Inventories	1,340		(866)		3,819

Prepaid and other current assets	(3,326)		(5,103)		3,694
Increase (decrease) in current liabilities:
Accounts payable	(25,455)		8,068		8,003

Accrued interest payable	12,922		1,632		(4,279)
Accrued liabilities	7,886		(19,740)		39,862
Taxes other than income tax	3,972		(5,276)		4,521

Changes in current assets and current liabilities	$	11,928	$	(44,765)	$	78,262

Schedule of Supplemental Cash Flow Information [Table Text Block]

Cash flows related to interest and income taxes were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Cash paid for interest, net of amount capitalized	$	204,511	$	176,859	$	183,078
Cash paid for income taxes, net of tax refunds received	$	3,260	$	6,817	$	8,535

Schedule of Cash and Cash Equivalents [Table Text Block]


	December 31,
	2020		2019
	(Thousands of Dollars)
Cash and cash equivalents	$	153,625	$	16,192
Other long-term assets, net	8,801		8,788
Cash, cash equivalents and restricted cash	$	162,426	$	24,980

EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

Disclosures for our Pension Plans and other postretirement benefit plans


	Pension Plans				Other Postretirement Benefit Plans
	2020		2019		2020		2019
	(Thousands of Dollars)
Change in benefit obligation:
Benefit obligation, January 1	$	167,257	$	141,833	$	13,196	$	10,908
Service cost	9,174		9,549		529		431
Interest cost	4,693		5,480		399		453
Benefits paid	(9,520)		(7,109)		(281)		(217)
Participant contributions	—		—		44		62
Actuarial loss	15,081		17,504		793		1,559
Benefit obligation, December 31	$	186,685	$	167,257	$	14,680	$	13,196
Change in plan assets:
Plan assets at fair value, January 1	$	159,036	$	126,949	$	—	$	—
Actual return on plan assets	21,758		28,064		—		—
Employer contributions	11,453		11,132		237		155
Benefits paid	(9,520)		(7,109)		(281)		(217)
Participant contributions	—		—		44		62
Plan assets at fair value, December 31	$	182,727	$	159,036	$	—	$	—
Reconciliation of funded status:
Fair value of plan assets at December 31	$	182,727	$	159,036	$	—	$	—
Less: Benefit obligation at December 31	186,685		167,257		14,680		13,196
Funded status at December 31	$	(3,958)	$	(8,221)	$	(14,680)	$	(13,196)
Amounts recognized in the consolidated balance sheets (a):
Accrued liabilities	$	(382)	$	(303)	$	(352)	$	(368)
Other long-term liabilities	(3,576)		(7,918)		(14,328)		(12,828)
Net pension liability	$	(3,958)	$	(8,221)	$	(14,680)	$	(13,196)

Accumulated benefit obligation	$	181,263	$	164,183	$	14,680	$	13,196

The components of net periodic benefit cost (income)

The components of net periodic benefit cost (income) related to our Pension Plans and other postretirement benefit plans were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
	(Thousands of Dollars)
Service cost	$	9,174	$	9,549	$	9,621	$	529	$	431	$	504
Interest cost	4,693		5,480		4,824		399		453		429
Expected return on plan assets	(8,972)		(8,015)		(7,417)		—		—		—
Amortization of prior service credit	(2,057)		(2,057)		(2,057)		(1,145)		(1,145)		(1,145)
Amortization of net actuarial loss	1,845		846		2,174		137		42		214
Excess Pension Plan settlement	136		—		—		—		—		—
Net periodic benefit cost (income)	$	4,819	$	5,803	$	7,145	$	(80)	$	(219)	$	2

Adjustments recognized in other comprehensive (loss) income

Adjustments to other comprehensive (loss) income related to our Pension Plans and other postretirement benefit plans were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
	(Thousands of Dollars)
Net unrecognized (loss) gain arising during the year:
Net actuarial (loss) gain	$	(2,159)	$	2,545	$	1,049	$	(793)	$	(1,559)	$	2,267

Net (gain) loss reclassified into income:
Amortization of prior service credit	(2,057)		(2,057)		(2,057)		(1,145)		(1,145)		(1,145)
Amortization of net actuarial loss	1,845		846		2,174		137		42		214
Net (gain) loss reclassified into income	(212)		(1,211)		117		(1,008)		(1,103)		(931)

Reclassification of stranded tax effects	—		—		(74)		—		—		—
Income tax benefit (expense)	28		14		(69)		—		—		(25)
Total changes to other comprehensive (loss) income	$	(2,343)	$	1,348	$	1,023	$	(1,801)	$	(2,662)	$	1,311

The amounts recorded as a component of accumulated other comprehensive (loss) income


	Pension Plans				Other Postretirement Benefit Plans
	December 31,				December 31,
	2020		2019		2020		2019
	(Thousands of Dollars)
Unrecognized actuarial loss	$	(24,878)	$	(24,564)	$	(3,846)	$	(3,190)
Prior service credit	10,433		12,490		6,029		7,174
Deferred tax asset	118		90		—		—
Accumulated other comprehensive (loss) income, net of tax	$	(14,327)	$	(11,984)	$	2,183	$	3,984

Schedule of fair value of plan assets

The major classes of plan assets measured at fair value for the Pension Plan were as follows:


	December 31, 2020
	Level 1		Level 2		Level 3		Total
	(Thousands of Dollars)
Cash equivalent securities	$	2,125	$	—	$	—	$	2,125
Equity securities:
U.S. large cap equity fund (a)	—		104,857		—		104,857
International stock index fund (b)	20,732		—		—		20,732
Fixed income securities:
Bond market index fund (c)	55,013		—		—		55,013
Total	$	77,870	$	104,857	$	—	$	182,727


	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(Thousands of Dollars)
Cash equivalent securities	$	160	$	—	$	—	$	160
Equity securities:
U.S. large cap equity fund (a)	—		92,737		—		92,737
International stock index fund (b)	17,473		—		—		17,473
Fixed income securities:
Bond market index fund (c)	48,666		—		—		48,666
Total	$	66,299	$	92,737	$	—	$	159,036

(b)This fund tracks the performance of the Total International Composite Index.

(c)This fund tracks the performance of the Barclays Capital U.S. Aggregate Bond Index.

Schedule of expected benefit payments

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid for the years ending December 31:


	Pension Plans		Other Postretirement Benefit Plans
	(Thousands of Dollars)
2021	$	9,771	$	352
2022	$	10,030	$	397
2023	$	10,329	$	451
2024	$	10,846	$	483
2025	$	11,558	$	529
2026-2030	$	61,321	$	3,355

Assumptions used to determine the benefit obligations

The weighted-average assumptions used to determine the benefit obligations were as follows:


	Pension Plans				Other Postretirement Benefit Plans
	December 31,				December 31,
	2020		2019		2020		2019
Discount rate	2.84	%	3.34	%	2.83	%	3.43	%
Rate of compensation increase	3.51	%	3.51	%	n/a		n/a
Cash balance interest crediting rate	2.00	%	2.00	%	n/a		n/a

Assumptions used to determine the net periodic benefit cost (income)

The weighted-average assumptions used to determine the net periodic benefit cost (income) were as follows:


	Pension Plans						Other Postretirement Benefit Plans
	Year Ended December 31,						Year Ended December 31,
	2020		2019		2018		2020		2019		2018
Discount rate	3.34	%	4.40	%	3.72	%	3.43	%	4.53	%	3.82	%
Expected long-term rate of return on plan assets	6.50	%	6.50	%	6.50	%	n/a		n/a		n/a
Rate of compensation increase	3.51	%	3.51	%	3.51	%	n/a		n/a		n/a
Cash balance interest crediting rate	2.00	%	2.90	%	2.00	%	n/a		n/a		n/a

Schedule of assumed health care cost trend rates

The assumed health care cost trend rates were as follows:


	December 31,
	2020		2019
Health care cost trend rate assumed for next year	6.84	%	6.84	%
Rate to which the cost trend rate was assumed to decrease (the ultimate trend rate)	5.00	%	5.00	%
Year that the rate reaches the ultimate trend rate	2028		2028

UNIT-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of long-term incentive plan compensation expense

The following table summarizes information pertaining to all of our long-term incentive plans:


	Units Outstanding December 31,			Compensation Expense Year Ended December 31,
	2020	2019	2018	2020		2019		2018
				(Thousands of Dollars)
Restricted units:
Domestic employees	2,235,125	1,223,143	1,028,484	$	10,205	$	9,437	$	8,233
Non-employee directors (NEDs)	98,769	61,349	59,752	631		774		524
International employees	19,987	10,243	30,918	58		711		1,158
Performance awards	87,122	161,561	158,326	1,291		4,172		1,889

Unit awards	—	—	—	—		22,941		18,895
Total	2,441,003	1,456,296	1,277,480	$	12,185	$	38,035	$	30,699

Restricted unit award activity

A summary of our equity-classified restricted unit awards is as follows:


	Measured at Grant Date Fair Value			Measured at Market Price
	Number of Units	Weighted-Average Fair Value Per Unit		Number of NEDs Units
Nonvested units as of January 1, 2018	736,746	$	35.95	27,097
Converted on July 20, 2018	53,447	24.99		18,915
Granted	518,282	24.07		34,303
Vested	(235,746)	35.12		(20,563)
Forfeited	(44,245)	36.05		—
Nonvested units as of December 31, 2018	1,028,484	29.47		59,752
Change in measurement (a)	59,752	20.93		(59,752)
Granted	596,881	26.46		—
Vested	(328,386)	30.11		—
Forfeited	(72,239)	28.05		—
Nonvested units as of December 31, 2019	1,284,492	27.48		—
Granted	1,454,998	12.10		—
Vested	(374,847)	28.47		—
Forfeited	(30,749)	26.75		—
Nonvested units as of December 31, 2020	2,333,894	17.70		—

Performance Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of long-term incentive plan compensation expense

A summary of our performance unit awards is shown below:


		Granted for Accounting Purposes
	Total Performance Unit Awards	Performance Unit Awards	Weighted-Average Grant Date Fair Value per Unit
Outstanding as of January 1, 2018	80,961	38,865	$	50.04
Granted	116,230	80,690	23.43


Forfeitures	(38,865)	(38,865)	50.04
Outstanding as of December 31, 2018	158,326	80,690	23.43
Granted	95,969	74,439	28.01
Vested	(80,690)	(80,690)	23.43
Forfeitures	(12,044)	—	—
Outstanding as of December 31, 2019	161,561	74,439	28.01
Granted	—	57,448	13.21
Performance adjustment (a)	72,951	72,951	28.01
Vested	(147,390)	(147,390)	28.01

Outstanding as of December 31, 2020	87,122	57,448	13.21

(a) Common units granted and issued upon vesting of performance units earned at 198% of target related to the performance awards granted in 2019 and 2018.

Share-based Payment Arrangement [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of long-term incentive plan compensation expense

A summary of our unit awards is shown below:


Date of Grant	Grant Date Fair Value		Unit Awards Granted	Common Units Issued, Net of Employee Withholding Tax
	(Thousands of Dollars)
February and March 2020	$	22,941	834,224	571,735
February 2019	$	17,537	704,886	482,971
July 2018	$	1,358	55,133	35,745

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

Components of income tax expense related to certain of our continuing operations conducted through separate taxable wholly owned corporate subsidiaries were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Current:
U.S.	$	36	$	3,741	$	4,515
Foreign	2,415		1,489		4,658
Foreign withholding tax	—		101		192
Total current	2,451		5,331		9,365

Deferred:
U.S.	300		(490)		1,403
Foreign	(621)		(168)		394
Foreign withholding tax	533		182		246
Total deferred	212		(476)		2,043

Less: amounts reported in discontinued operations	—		101		1,251

Income tax expense	$	2,663	$	4,754	$	10,157

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The tax effects of significant temporary differences representing deferred income tax assets and liabilities were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Deferred income tax assets:
Net operating losses	$	18,459	$	26,081
Employee benefits	134		372
Environmental and legal reserves	105		267

Capital loss	10,813		3,870
Other	834		693
Total deferred income tax assets	30,345		31,283
Less: Valuation allowance	(28,211)		(17,743)
Net deferred income tax assets	2,134		13,540

Deferred income tax liabilities:
Property, plant and equipment	(13,772)		(25,169)
Foreign withholding tax	(1,002)		(433)
Other	(371)		(365)
Total deferred income tax liabilities	(15,145)		(25,967)

Net deferred income tax liability	$	(13,011)	$	(12,427)

SEGMENT INFORMATION (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Text Block]

Results of operations for the reportable segments were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Revenues:
Pipeline	$	718,823	$	701,830	$	611,065

Storage:
Third parties	494,396		453,976		443,546
Intersegment	46		25		42
Total storage	494,442		454,001		443,588

Fuels marketing	268,345		342,215		465,651
Consolidation and intersegment eliminations	(46)		(25)		(42)
Total revenues	$	1,481,564	$	1,498,021	$	1,520,262

Depreciation and amortization expense:
Pipeline	$	177,384	$	166,991	$	153,943
Storage	99,092		97,573		93,345

Total segment depreciation and amortization expense	276,476		264,564		247,288
Other depreciation and amortization expense	8,625		8,360		8,604
Total depreciation and amortization expense	$	285,101	$	272,924	$	255,892

Operating income:
Pipeline	$	118,429	$	332,480	$	272,695
Storage	189,781		154,105		155,708
Fuels marketing	12,233		20,578		15,964
Consolidation and intersegment eliminations	—		(32)		32
Total segment operating income	320,443		507,131		444,399
General and administrative expenses	102,716		107,855		100,067
Other depreciation and amortization expense	8,625		8,360		8,604


Total operating income	$	209,102	$	390,916	$	335,728

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

Revenues by geographic area are shown in the table below:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
United States	$	1,441,892	$	1,465,135	$	1,481,844
Foreign	39,672		32,886		38,418
Consolidated revenues	$	1,481,564	$	1,498,021	$	1,520,262

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

Total amounts of property, plant and equipment, net by geographic area were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
United States	$	3,837,550	$	4,000,647
Foreign	119,962		118,332
Consolidated property, plant and equipment, net	$	3,957,512	$	4,118,979

Schedule of Segment Reporting Information Assets By Segment [Text Block]

Total assets by reportable segment were as follows:


	December 31,
	2020		2019
	(Thousands of Dollars)
Pipeline	$	3,609,508	$	3,884,819
Storage	1,897,167		2,082,832
Fuels marketing	31,967		31,064
Total segment assets	5,538,642		5,998,715

Other partnership assets	278,376		187,277
Total consolidated assets	$	5,817,018	$	6,185,992

Schedule of Capital Expenditures, by Segment [Table Text Block]

Capital expenditures, including acquisitions, by reportable segment were as follows:


	Year Ended December 31,
	2020		2019		2018
	(Thousands of Dollars)
Pipeline	$	122,512	$	387,702	$	288,035
Storage	71,788		141,972		202,782

Other partnership assets	3,779		3,894		4,137
Total capital expenditures	$	198,079	$	533,568	$	494,954

ORGANIZATION AND OPERATIONS Narrative 1 - Goodwill Impairment (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Oct. 01, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unusual or Infrequent Item, or Both [Line Items]
Goodwill impairment loss	$ 0		$ 225,000	$ 0	$ 0
Crude Oil Pipelines \| Pipeline Segment
Unusual or Infrequent Item, or Both [Line Items]
Goodwill impairment loss		$ 225,000	$ 225,000

ORGANIZATION AND OPERATIONS Narrative 2 - Texas City Sale (Details) $ in Thousands		12 Months Ended
	Dec. 07, 2020 USD ($)	Dec. 31, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of terminals sold	2
Proceeds from sale	$ 106,000
Loss on sale		$ (34,700)

ORGANIZATION AND OPERATIONS Narrative 3 - Senior Notes (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 14, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2020
Debt Instrument [Line Items]
Proceeds from note offerings, net of issuance costs	$ 1,182,000	$ 1,182,035	$ 491,580	$ 0
5.75% senior notes
Debt Instrument [Line Items]
Long-term debt	$ 600,000	600,000	0
Long-term debt, rate	5.75%
6.375% senior notes
Debt Instrument [Line Items]
Long-term debt	$ 600,000	600,000	0
Long-term debt, rate	6.375%
4.80% senior notes
Debt Instrument [Line Items]
Long-term debt		$ 0	$ 450,000		$ 450,000
Long-term debt, rate					4.80%
Logistics Notes due 2025 and Logistics Notes due 2030
Debt Instrument [Line Items]
Long-term debt, issuance costs	$ 18,000

ORGANIZATION AND OPERATIONS Narrative 4 - Term Loan (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 15, 2020	Apr. 21, 2020
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (137,900)	$ (141,746)	$ 0	$ 0
Unsecured Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 750,000
Long-term debt, term						3 years
The Term Loan, Initial Loan					$ 500,000	$ 500,000

ORGANIZATION AND OPERATIONS Narrative 5 - Selby Terminal Fire (Details) - USD ($) $ in Thousands		2 Months Ended	3 Months Ended	12 Months Ended
	Oct. 15, 2019	Feb. 28, 2021	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unusual or Infrequent Item, or Both [Line Items]
(Gain) loss, property damage				$ 0	$ 0	$ (78,756)
Selby, California Fire [Member]
Unusual or Infrequent Item, or Both [Line Items]
Unusual or infrequent item, or both, nature of event or transaction	our terminal facility in Selby, California experienced a fire that destroyed two storage tanks and temporarily shut down the terminal
(Gain) loss, property damage			$ 5,400
Insurance proceeds				35,000
Selby, California Fire [Member] \| Subsequent Event [Member]
Unusual or Infrequent Item, or Both [Line Items]
Insurance proceeds		$ 20,500
Selby, California Fire [Member] \| Operating Expense [Member] \| Business Interruption Loss from Selby, California Fire [Member]
Unusual or Infrequent Item, or Both [Line Items]
Insurance proceeds				$ 6,700

ORGANIZATION AND OPERATIONS Narrative 6 - Sale of St. Eustatius (Details) - USD ($) $ in Thousands			12 Months Ended
	Dec. 07, 2020	Jul. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale	$ 106,000
Asset and goodwill impairment losses			$ 225,000	$ 336,838	$ 0
The St. Eustatius Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale		$ 230,000

ORGANIZATION AND OPERATIONS Narrative 7 - Sale of European Operations (Details) $ in Thousands			12 Months Ended
	Dec. 07, 2020 USD ($)	Nov. 30, 2018 USD ($) bbl	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale	$ 106,000
Description of assets sold	The two terminals have an aggregate storage capacity of 3.0 million barrels and were previously included in our storage segment.
Loss on sale			$ (34,700)
The European Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale		$ 270,000
Description of assets sold		six liquids storage terminals in the United Kingdom and one facility in Amsterdam
Storage capacity, in barrels \| bbl		9,500,000
Loss on sale				$ 0	$ (43,366)

ORGANIZATION AND OPERATIONS Narrative 8 - Merger (Details)	Jul. 20, 2018 Rate
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common unit conversion rate	55.00%

ORGANIZATION AND OPERATIONS Narrative 9 - Hurricane Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unusual or Infrequent Item, or Both [Line Items]
(Gain) loss, property damage	$ 0	$ 0	$ (78,756)
Hurricane damage at St. Eustatius terminal [Member]
Unusual or Infrequent Item, or Both [Line Items]
Insurance proceeds			87,500
Hurricane damage at St. Eustatius terminal [Member] \| Business Interruption Loss From Hurricane [Member]
Unusual or Infrequent Item, or Both [Line Items]
Insurance proceeds			9,100
(Loss) income from discontinued operations, net of tax [Member] \| Hurricane damage at St. Eustatius terminal [Member]
Unusual or Infrequent Item, or Both [Line Items]
(Gain) loss, property damage			$ (78,800)

ORGANIZATION AND OPERATIONS Narrative 10 - Operations (Details) bbl in Millions	12 Months Ended
	Dec. 31, 2020 mi bbl
Segment Information
Number of business segments	3
Pipeline Segment \| Central West Refined Products Pipelines
Segment Information
Pipeline length, in miles	3,205
Pipeline Segment \| Crude Oil Pipelines
Segment Information
Pipeline length, in miles	2,205
Storage capacity, in barrels \| bbl	5.6
Pipeline Segment \| East and North Pipelines
Segment Information
Pipeline length, in miles	2,500
Storage capacity, in barrels \| bbl	7.4
Pipeline Segment \| Ammonia Pipeline
Segment Information
Pipeline length, in miles	2,000
Storage Segment
Segment Information
Storage capacity, in barrels \| bbl	59.0

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Narrative (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended	12 Months Ended
	Oct. 01, 2020	Mar. 31, 2020	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Goodwill impairment loss	$ 0			$ 225,000	$ 0	$ 0
Asset impairment losses					305,700
Unrecognized tax benefits				$ 0	0
Tax years subject to examination				For U.S. federal and state purposes, as well as for our major non-U.S. jurisdictions, tax years subject to examination are 2016 through 2019, according to standard statute of limitations.
Payment terms				Generally, payment terms do not exceed 30 days.
Common unitholders ownership interest			98.00%
General partner ownership interest			2.00%
Goodwill				$ 766,416	1,005,853	1,005,853
Pipeline Segment
Goodwill				479,231	704,231	704,231
St. Eustatius Bunkers [Member]
Goodwill						$ 31,100	$ 0
Crude Oil Pipelines \| Pipeline Segment
Goodwill impairment loss		$ 225,000		225,000
Reporting unit, percentage of fair value in excess of carrying amount	4.00%
Goodwill				308,600
Other long-term assets, net
Restricted cash				$ 8,800	$ 8,800

DISPOSITIONS AND DISCONTINUED OPERATIONS Narrative (Details) $ in Thousands					3 Months Ended		12 Months Ended
	Dec. 07, 2020 USD ($)	Oct. 01, 2020 USD ($)	Jul. 29, 2019 USD ($)	Nov. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of terminals sold	2
Proceeds from sale or disposition of assets							$ 110,640	$ 228,152	$ 270,440
Description of assets sold	The two terminals have an aggregate storage capacity of 3.0 million barrels and were previously included in our storage segment.
Asset impairment losses								305,700
Goodwill impairment loss		$ 0					225,000	0	0
Goodwill							766,416	1,005,853	1,005,853
Proceeds from sale	$ 106,000
Loss on sale							$ (34,700)
Income (Loss) from Discontinued Operations, Net of Tax
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment losses					$ 8,400	$ 297,300
(Loss) income from discontinued operations, net of tax [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from sale of the St. Eustatius Operations								3,900
The European Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Description of assets sold				six liquids storage terminals in the United Kingdom and one facility in Amsterdam
Proceeds from sale				$ 270,000
Loss on sale								0	(43,366)
The European Disposition [Member] \| (Loss) income from discontinued operations, net of tax [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale									(43,400)
The St. Eustatius Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Description of assets sold			The St. Eustatius Disposition included a 14.3 million barrel storage and terminalling facility and related assets on the island of St. Eustatius in the Caribbean Netherlands.
Proceeds from sale			$ 230,000
Loss from sale of the St. Eustatius Operations								$ 3,942	0
St. Eustatius Bunkers [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill						0			$ 31,100
St. Eustatius Bunkers [Member] \| Income (Loss) from Discontinued Operations, Net of Tax
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment loss						$ 31,100

DISPOSITIONS AND DISCONTINUED OPERATIONS Table 1 - Discontinued Operations Income Statement Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Revenues		$ 248,981	$ 441,495
Cost of revenues		220,595	407,256
Impairment losses		336,838	0
General and administrative expenses (excluding depreciation and amortization expense)		1,231	6,133
Other depreciation and amortization expense		0	271
Total costs and expenses		558,664	413,660
Operating (loss) income		(309,683)	27,835
Interest income, net		32
Interest expense, net			(1,839)
Other expense, net		(2,775)
Other income, net			34,674
(Loss) income from discontinued operations before income tax expense		(312,426)	60,670
Income tax expense	$ 0	101	1,251
(Loss) income from discontinued operations, net of tax	$ 0	$ (312,527)	$ 59,419

DISPOSITIONS AND DISCONTINUED OPERATIONS Table 2 - Discontinued Operations Cash Flow Disclosures (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment losses			$ 305,700
Goodwill impairment loss	$ 0	$ 225,000	0	$ 0
Loss on sale		34,700
Gain from insurance recoveries		$ 0	0	(78,756)
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Capital expenditures			(27,954)	(114,811)
Depreciation and amortization expense			8,536	41,982
Asset impairment losses			305,715	0
Goodwill impairment loss			31,123	0
Gain from insurance recoveries			0	(78,756)
The St. Eustatius Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from sale of the St. Eustatius Operations			3,942	0
The European Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale			$ 0	$ 43,366

MERGER AND RELATED PARTY AGREEMENTS Narrative 1 (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 20, 2018
Class of Stock [Line Items]
General partner ownership interest	2.00%
Common unit conversion rate						55.00%
Approximate cash consideration for merger					$ 68.0
Number of common limited partner units owned by general partner	10,200,000
Common Limited Partner [Member]
Class of Stock [Line Items]
Issuance of NuStar Energy common units as a result of the Merger, units issued		23,600,000
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued		13,400,000	0	0	13,409,593

MERGER AND RELATED PARTY AGREEMENTS Table - Merger Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 20, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Fair value of incremental NS common units issued	$ 335,106
Holdings debt and assumed net current liabilities	52,075
Transaction costs	15,897
Total consideration	403,078
Carrying value of general partner interest	$ 25,999
Loss to common unitholders attributable to the Merger		$ 0	$ 0	$ (377,079)
Basic weighted-average common units outstanding		109,155,117	107,789,030	99,490,495
Loss per common unit attributable to the Merger				$ (3.79)

MERGER AND RELATED PARTY AGREEMENTS Narrative 2 (Details)	12 Months Ended
	Dec. 31, 2020
NuStar GP, LLC [Member]
Related Party Transaction [Line Items]
Administrative fees, description	(the Amended GP Services Agreement), which provided that we furnish administrative services necessary to conduct the business of Holdings, and Holdings compensated us for these services for an annual fee of $1.0 million, subject to adjustment based on the annual merit increase percentage applicable to our employees for the most recently completed fiscal year and for changes in level of service. We terminated the Amended GP Services Agreement in conjunction with the Merger.

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 1 - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contract assets
Noncurrent portion	$ 932	$ 1,003	$ 539	$ 171
Total	3,626	3,143	2,605	2,127
Additions	5,686	4,890	3,281
Transfer to accounts receivable	(4,828)	(4,352)	(2,803)
Transfer to revenues, including amounts reported in discontinued operations, contract assets	(375)	0	0
Total activity	483	538	478
Contract liabilities
Current portion/Held for sale	(22,019)	(21,083)
Noncurrent portion	(47,537)	(40,289)	(38,945)	(46,361)
Total	(69,556)	(61,372)	(85,881)	(60,464)
Additions	(69,830)	(52,957)	(83,243)
Transfer to revenues, including amounts reported in discontinued operations, contract liabilities	61,646	77,466	57,826
Total activity	(8,184)	24,509	(25,417)
Other current assets
Contract assets
Current portion/Held for sale	2,694	2,140	2,066	1,956
Accrued liabilities
Contract liabilities
Current portion/Held for sale	(22,019)	(21,083)	(21,579)	(13,801)
Assets Held for Sale [Member]
Contract assets
Current portion/Held for sale	0	0	0	0
Liabilities held for sale [Member]
Contract liabilities
Current portion/Held for sale	$ 0	$ 0	$ (25,357)	$ (302)

REVENUE FROM CONTRACTS WITH CUSTOMERS Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended			15 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Revenue recognized			$ 61,646	$ 77,466	$ 57,826
Additions to contract liability			$ (69,830)	$ (52,957)	$ (83,243)
Revenue recognized due to change in contract liability		$ 9,000
Unnamed Customer [Member]
Revenue recognized						$ 37,500
Additions to contract liability	$ (37,500)

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 2 - Expected Timing of Satisfaction of Performance Obligations (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 1,589,268
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 486,339
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 354,666
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 261,205
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 184,862
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 128,279
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 173,917
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 3 - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,481,564	$ 1,498,021	$ 1,520,262
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	(46)	(25)	(42)
Pipeline Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	716,898	693,005	611,011
Lessor revenues	1,925	8,825	54
Revenues	718,823	701,830	611,065
Pipeline Segment \| Crude Oil Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	329,105	316,417	248,261
Pipeline Segment \| Refined Products and Ammonia Pipelines [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	387,793	376,588	362,750
Storage Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	453,128	413,227	403,739
Lessor revenues	41,314	40,774	39,849
Revenues	494,442	454,001	443,588
Storage Segment \| Throughput Terminal [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	136,632	114,243	83,157
Storage Segment \| Storage Terminal [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	316,496	298,984	320,582
Fuels Marketing Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer	268,345	342,215	465,651
Revenues	$ 268,345	$ 342,215	$ 465,651

ALLOWANCE FOR CREDIT LOSSES Table - Balance of and Changes in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Credit Loss [Abstract]
Balance as of beginning of year	$ 72	$ 9,412	$ 9,380
Current period provision for credit losses	441	2,322	233
Write-offs charged against the allowance	(513)	(11,662)	(201)
Balance as of end of year	$ 0	$ 72	$ 9,412

INVENTORIES Table - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Petroleum products	$ 7,394	$ 8,646
Materials and supplies	3,665	3,747
Total	$ 11,059	$ 12,393

PROPERTY, PLANT AND EQUIPMENT Table - Property, Plant and Equipment, at Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 6,164,742	$ 6,187,144
Less accumulated depreciation and amortization	(2,207,230)	(2,068,165)
Property, plant and equipment, net	3,957,512	4,118,979
Land, Buildings and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	440,358	444,156
Pipelines, storage and terminals
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	5,253,507	5,162,426
Rights-of-way
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	359,441	350,026
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 111,436	$ 230,536
Minimum [Member] \| Land, Buildings and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	0 years
Minimum [Member] \| Pipelines, storage and terminals
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	15 years
Minimum [Member] \| Rights-of-way
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Maximum [Member] \| Land, Buildings and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Maximum [Member] \| Pipelines, storage and terminals
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Maximum [Member] \| Rights-of-way
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years

PROPERTY, PLANT AND EQUIPMENT Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Capitalized interest costs	$ 4.9	$ 8.9	$ 7.8
Depreciation and amortization expense for property, plant and equipment	$ 228.8	$ 226.0	$ 243.5

INTANGIBLE ASSETS Table - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Intangible Assets [Line Items]
Cost	$ 866,259	$ 866,259
Accumulated Amortization	$ (236,050)	(184,627)
Customer contracts and relationships
Intangible Assets [Line Items]
Weighted-average amortization period	18 years
Cost	$ 863,900	863,900
Accumulated Amortization	$ (235,205)	(183,832)
Other
Intangible Assets [Line Items]
Weighted-average amortization period	47 years
Cost	$ 2,359	2,359
Accumulated Amortization	$ (845)	$ (795)

INTANGIBLE ASSETS Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization expense	$ 51,400	$ 51,400	$ 51,400
2021	51,000
2022	51,000
2023	45,000
2024	45,000
2025	$ 38,000

GOODWILL Table - Balances of and Changes in the Carrying Amount of Goodwill by Segment (Details) - USD ($) $ in Thousands			3 Months Ended	12 Months Ended
	Dec. 07, 2020	Oct. 01, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill				$ 766,416	$ 1,005,853	$ 1,005,853
Goodwill impairment loss		$ 0		(225,000)	0	0
Goodwill, accumulated impairment loss				(225,000)
Texas City Sale	$ (14,437)
Goodwill, gross				991,416
Pipeline Segment
Goodwill [Roll Forward]
Goodwill				479,231	704,231	704,231
Goodwill, accumulated impairment loss				(225,000)
Goodwill, gross				704,231
Pipeline Segment \| Crude Oil Pipelines
Goodwill [Roll Forward]
Goodwill				308,600
Goodwill impairment loss			$ (225,000)	(225,000)
Texas City Sale	0
Storage Segment
Goodwill [Roll Forward]
Goodwill				287,185	$ 301,622	$ 301,622
Goodwill impairment loss				0
Goodwill, accumulated impairment loss				0
Texas City Sale	$ (14,437)
Goodwill, gross				$ 287,185

GOODWILL Narrative (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
GOODWILL Narrative (Details) - USD ($) $ in Thousands	Oct. 01, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Goodwill [Line Items]
Goodwill impairment loss	$ 0		$ 225,000	$ 0	$ 0
Goodwill			766,416	1,005,853	1,005,853
Pipeline Segment
Goodwill [Line Items]
Goodwill			479,231	$ 704,231	704,231
St. Eustatius Bunkers [Member]
Goodwill [Line Items]
Goodwill					$ 31,100	$ 0
Crude Oil Pipelines \| Pipeline Segment
Goodwill [Line Items]
Goodwill impairment loss		$ 225,000	225,000
Goodwill			$ 308,600

ACCRUED LIABILITIES Table - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities, Current [Abstract]
Employee wages and benefit costs	$ 27,805	$ 36,704
Revenue contract liabilities	22,019	21,083
Interest rate swaps	0	19,169
Operating lease liabilities	10,890	10,416
Environmental costs	5,371	4,837
Other	11,685	16,401
Accrued liabilities	$ 77,770	$ 108,610

DEBT Table 1 - Short-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Current portion of finance leases (refer to Note 16)	$ 3,839	$ 4,546
Short-term line of credit
Debt Instrument [Line Items]
Short-term debt	$ 0	$ 5,500

DEBT Table 2 - Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 14, 2020	Aug. 31, 2020	Dec. 31, 2019	May 22, 2019
Debt Instrument [Line Items]
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	$ (42,382)			$ (23,301)
Total long-term debt	3,539,258			3,331,839
Finance leases (refer to Note 16)	54,238			55,446
Less current portion	0			452,367
Long-term debt, less current portion	3,593,496			2,934,918
Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term debt	0			475,000
4.80% senior notes
Debt Instrument [Line Items]
Long-term debt	0		$ 450,000	450,000
6.75% senior notes
Debt Instrument [Line Items]
Long-term debt	300,000			300,000
4.75% senior notes
Debt Instrument [Line Items]
Long-term debt	250,000			250,000
5.75% senior notes
Debt Instrument [Line Items]
Long-term debt	600,000	$ 600,000		0
6.00% senior notes
Debt Instrument [Line Items]
Long-term debt	500,000			500,000	$ 500,000
5.625% senior notes
Debt Instrument [Line Items]
Long-term debt	550,000			550,000
6.375% senior notes
Debt Instrument [Line Items]
Long-term debt	600,000	$ 600,000		0
Subordinated Notes
Debt Instrument [Line Items]
Long-term debt	402,500			402,500
Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Long-term debt	322,140			365,440
Receivables Financing Agreement
Debt Instrument [Line Items]
Long-term debt	$ 57,000			$ 62,200

DEBT Table 3 - Long-Term Debt Repayments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Long-term Debt, Fiscal Year Maturity [Abstract]
2021	$ 300,000
2022	250,000
2023	57,000
2024	0
2025	600,000
Thereafter	2,374,640
Total repayments	3,581,640
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	(42,382)	$ (23,301)
Total long-term debt	$ 3,539,258	$ 3,331,839

DEBT Narrative 2 - Interest and Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Interest payments	$ 207.2	$ 183.8	$ 190.9
Amortization of debt issuance costs and debt discount	$ 11.4	$ 6.5	$ 7.1

DEBT Narrative 3 - Term Loan (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 16, 2020	Apr. 21, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 15, 2020	Sep. 14, 2020
Debt Instrument [Line Items]
Loss on extinguishment of debt				$ (137,900)	$ (141,746)	$ 0	$ 0
Early Repayment Premiums [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (97,600)
Unamortized Debt Issuance Costs, Unamortized Discount, and Commitment Fee [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (40,300)
Unsecured Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 750,000
Long-term debt, term		3 years
The Term Loan, Initial Loan		$ 500,000						$ 500,000
Debt instrument, unamortized discount		$ 22,500
Original issue discount		3.00%
Long-term debt, issuance costs		$ 14,400
Long-term debt, rate		12.00%
Debt instrument, unused borrowing capacity, amount					$ 250,000
Commitment fee		5.00%
Debt instrument, payment terms			Upon issuance of the $1.2 billion of senior notes in September 2020, we were required to repay outstanding borrowings under the Term Loan and pay a make-whole premium for liquidated damages and compensation for the costs of making funds available. From the Initial Loan Funding Date through the 18-month anniversary of the Initial Loan Funding Date, such premium was the sum of (i) the make-whole amount and (ii) 6.25% of the aggregate principal amount of borrowings then paid.
5.75% senior notes
Debt Instrument [Line Items]
Long-term debt, rate									5.75%
6.375% senior notes
Debt Instrument [Line Items]
Long-term debt, rate									6.375%

DEBT Narrative 4 - Revolving Credit Agreement (Details) - Revolving Credit Agreement [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,000,000	$ 1,200,000
Line of credit facility, covenant terms	The Revolving Credit Agreement is subject to maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio requirements, which may limit the amount we can borrow to an amount less than the total amount available for borrowing. For the rolling period ending December 31, 2020, the maximum allowed consolidated debt coverage ratio (as defined in the Revolving Credit Agreement) may not exceed 5.00-to-1.00 and the minimum consolidated interest coverage ratio (as defined in the Revolving Credit Agreement), must not be less than 1.75-to-1.00. If we complete one or more acquisitions for aggregate net consideration of at least $50.0 million, our maximum consolidated debt coverage ratio will increase to 5.50-to-1.00 for two rolling periods. The Revolving Credit Agreement also contains customary restrictive covenants, such as limitations on indebtedness, liens, mergers, asset transfers and certain investing activities.
Current remaining borrowing capacity	$ 994,800
Long-term debt	0	$ 475,000
Letters of credit outstanding, amount	5,200
Line of credit facility, maximum letters of credit	$ 400,000
Line of credit facility, interest rate description	The interest rate on the Revolving Credit Agreement is subject to adjustment if our debt rating is downgraded (or upgraded) by certain credit rating agencies. In August of 2020, Moody’s Investor Service Inc. downgraded our credit rating from Ba2 to Ba3. This rating downgrade caused the interest rate on our Revolving Credit Agreement to increase by 0.25% effective August 2020. The Revolving Credit Agreement is the only debt arrangement with an interest rate that is subject to adjustment if our debt rating is downgraded (or upgraded) by certain credit rating agencies.
Line of credit facility, interest rate during period	3.30%

DEBT Narrative 5 - Senior Notes (Details) - USD ($) $ in Thousands			12 Months Ended
	Sep. 14, 2020	May 22, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2021	Aug. 31, 2020	Apr. 15, 2018
Debt Instrument [Line Items]
Proceeds from note offerings, net of issuance costs	$ 1,182,000		$ 1,182,035	$ 491,580	$ 0
5.75% senior notes
Debt Instrument [Line Items]
Long-term debt	$ 600,000		$ 600,000	0
Long-term debt, rate	5.75%
Debt instrument, redemption, description			If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase.
6.375% senior notes
Debt Instrument [Line Items]
Long-term debt	$ 600,000		$ 600,000	0
Long-term debt, rate	6.375%
Debt instrument, redemption, description			If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase.
4.80% senior notes
Debt Instrument [Line Items]
Long-term debt			$ 0	450,000			$ 450,000
Long-term debt, rate							4.80%
6.00% senior notes
Debt Instrument [Line Items]
Long-term debt		$ 500,000	$ 500,000	500,000
Long-term debt, rate			6.00%
Proceeds from note offerings, net of issuance costs		$ 491,600
Debt instrument, redemption, description			If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase.
7.65% senior notes
Debt Instrument [Line Items]
Long-term debt								$ 350,000
Long-term debt, rate								7.65%
6.75% senior notes
Debt Instrument [Line Items]
Long-term debt			$ 300,000	300,000
Long-term debt, rate			6.75%
Debt instrument, redemption, description			If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase.
6.75% senior notes \| Subsequent Event [Member]
Debt Instrument [Line Items]
Long-term debt						$ 300,000
Long-term debt, rate						6.75%
4.75% senior notes
Debt Instrument [Line Items]
Long-term debt			$ 250,000	250,000
Long-term debt, rate			4.75%
5.625% senior notes
Debt Instrument [Line Items]
Long-term debt			$ 550,000	$ 550,000
Long-term debt, rate			5.625%
Debt instrument, redemption, description			If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 5.75% senior notes, the 6.0% senior notes, the 5.625% senior notes or the 6.375% senior notes, each holder of the applicable senior notes may require us to repurchase all or a portion of its notes at a price equal to 101% of the principal amount of the notes repurchased, plus any accrued and unpaid interest to the date of repurchase.

DEBT Narrative 6 - Subordinated Notes (Details) - Subordinated Notes - USD ($) $ in Thousands		12 Months Ended
	Jan. 15, 2018	Dec. 31, 2020	Dec. 31, 2019	Jan. 14, 2018
Debt Instrument [Line Items]
Long-term debt		$ 402,500	$ 402,500
Long-term debt, rate		7.00%		7.625%
Debt instrument, interest rate terms		an annual rate equal to the sum of the three-month LIBOR for the related quarterly interest period, plus 6.734% payable quarterly, commencing April 15, 2018, unless payment is deferred in accordance with the terms of the notes. NuStar Logistics may elect to defer interest payments on the Subordinated Notes on one or more occasions for up to five consecutive years.
Debt instrument, redemption price, percentage	100.00%

DEBT Narrative 7 - GoZone Bonds (Details) - USD ($)				12 Months Ended
DEBT Narrative 7 - GoZone Bonds (Details) - USD ($)	Sep. 14, 2020	Jun. 03, 2020	Mar. 04, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term debt repayments				$ 1,813,963,000	$ 928,900,000	$ 1,746,776,000
Proceeds from note offerings, net of issuance costs	$ 1,182,000,000.0			1,182,035,000	491,580,000	$ 0
Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Long-term debt				322,140,000	365,440,000
Long-term debt repayments			$ 43,300,000
Proceeds from note offerings, net of issuance costs		$ 0
Proceeds received				$ 0	$ 0

DEBT Table 4 - GoZone Bonds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Go Zone Bonds Due June 2038
Debt Instrument [Line Items]
Date issued	Jun. 26, 2008
Long-term debt	$ 55,440
Long-term debt, rate	6.10%
Maturity date	Jun. 01, 2038
Go Zone Bonds Due July 2040
Debt Instrument [Line Items]
Date issued	Jul. 15, 2010
Long-term debt	$ 100,000
Long-term debt, rate	6.35%
Maturity date	Jul. 01, 2040
Go Zone Bonds Due October 2040
Debt Instrument [Line Items]
Date issued	Oct. 07, 2010
Long-term debt	$ 43,300
Long-term debt, rate	6.35%
Maturity date	Oct. 01, 2040
Go Zone Bonds Due December 2040
Debt Instrument [Line Items]
Date issued	Dec. 29, 2010
Long-term debt	$ 48,400
Long-term debt, rate	6.10%
Maturity date	Dec. 01, 2040
Go Zone Bonds Due August 2041
Debt Instrument [Line Items]
Date issued	Aug. 09, 2011
Long-term debt	$ 75,000
Long-term debt, rate	5.85%
Maturity date	Aug. 01, 2041
Total Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Long-term debt	$ 322,140	$ 365,440
Debt instrument description	Interest on the GoZone Bonds accrues from June 3, 2020 and is payable semi-annually on June 1 and December 1 of each year, beginning December 1, 2020. The holders of the Series 2008, Series 2010B and Series 2011 GoZone Bonds are required to tender their bonds at the applicable mandatory purchase date in exchange for 100% of the principal plus accrued and unpaid interest, after which these bonds will potentially be remarketed with a new interest rate established. Each of the Series 2010 and Series 2010A GoZone Bonds is subject to redemption on or after June 1, 2030 by the Parish of St. James, at our option, in whole or in part, at a redemption price of 100% of the principal amount to be redeemed plus accrued interest. The Series 2008, Series 2010B and Series 2011 GoZone Bonds are not subject to optional redemption. NuStar Logistics’ agreements with the Parish of St. James related to the GoZone Bonds contain (i) customary restrictive covenants that limit the ability of NuStar Logistics and its subsidiaries, to, among other things, create liens or enter into sale-leaseback transactions, consolidations, mergers or asset sales and (ii) a change of control provision that provides each holder the right to require the trustee, with funds provided by NuStar Logistics, to repurchase all or a portion of that holder’s GoZone Bonds upon a change of control at a price equal to 101% of the aggregate principal amount repurchased, plus any accrued and unpaid interest.

DEBT Narrative 8 - Receivables Financing Agreement (Details) - Receivables Financing Agreement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Sep. 02, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 100.0	$ 125.0
Debt instrument, collateral amount	$ 110.6		$ 112.8
Weighted average annual interest rate	1.90%

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS Table 1 - Balance of and Changes in Accruals for Environmental Matters (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance as of the beginning of year	$ 7,938	$ 7,753
Additions to accrual	3,692	3,700
Payments	(3,257)	(3,515)
Balance as of the end of year	$ 8,373	$ 7,938

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS Table 2 - Accruals for Environmental Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies, Balance Sheet Classification [Abstract]
Accrued liabilities	$ 5,371	$ 4,837
Other long-term liabilities	3,002	3,101
Accruals for environmental matters	$ 8,373	$ 7,938	$ 7,753

COMMITMENTS AND CONTINGENCIES Table - Commitments (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2021	$ 9,980
2022	7,647
2023	2,039
2024	1,025
2025	483
Thereafter	4,520
Total	$ 25,694

COMMITMENTS AND CONTINGENCIES Narrative 1 - Commitments (Details)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Description of purchase obligations	Our purchase obligations primarily consist of an eleven-year chemical supply agreement related to our pipelines that terminates in 2022 and various service agreements with information technology providers.

COMMITMENTS AND CONTINGENCIES Narrative 2 (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Loss contingency accrual, at carrying value	$ 2.6	$ 3.7

LEASE ASSETS AND LIABILITIES Narrative 1 (Details) $ in Millions	Jan. 01, 2019 USD ($)
Leases [Abstract]
Right-of-Use Assets Recognized at Transition	$ 207.0
Lease Liabilities Recognized at Transition	$ 192.0

LEASE ASSETS AND LIABILITIES Narrative 2 (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Operating Lease Type [Line Items]
Operating lease, liability	$ 85,789	$ 80,499
Operating lease, right-of-use asset	$ 87,443	$ 81,219
Lessee, Finance Lease, Description [Abstract]
Lessee, Finance Lease, Description	The primary component of our finance lease portfolio is a dock at a terminal facility, which includes a commitment for minimum dockage and wharfage throughput volumes.
Finance lease remaining term	The dock lease has a remaining initial term of less than one year
Number of renewal periods	4
Lessee, finance lease, renewal term	5 years
Land and dock leases [Member]
Operating Lease Type [Line Items]
Lessee, operating lease, description	Our operating leases consist primarily of land and dock leases at various terminal facilities.
Land and dock leases [Member] \| Maximum [Member]
Operating Lease Type [Line Items]
Lessee, operating lease, remaining term	5 years
Lessee, operating lease, renewal term	20 years
Marine vessel leases [Member]
Operating Lease Type [Line Items]
Lessee, operating lease, description	three leases for marine vessels at our Point Tupper terminal facility
Lessee, operating lease, term of contract	5 years
Operating lease, liability	$ 20,100
Operating lease, right-of-use asset	$ 20,100

LEASE ASSETS AND LIABILITIES Table 1 (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease, right-of-use asset	$ 87,443	$ 81,219
Finance lease, right-of-use asset	73,319	74,953
Finance lease, right-of-use asset, accumulated amortization	8,444	3,748
Operating lease liabilities, current	10,890	10,416
Operating lease liabilities, noncurrent	74,899	70,083
Total operating lease liabilities	85,789	80,499
Finance lease liability, current	3,839	4,546
Finance lease liability, noncurrent	54,238	55,446
Total finance lease liabilities	$ 58,077	$ 59,992
Operating lease, right-of-use asset, statement of financial position [extensible list]	us-gaap:OtherAssets	us-gaap:OtherAssets
Finance lease, right-of-use asset, statement of financial position [extensible list]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Operating lease, liability, current, statement of financial position [extensible list]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Operating lease, liability, noncurrent, statement of financial position [extensible list]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Finance lease, liability, current, statement of financial position [extensible list]	us-gaap:DebtCurrent	us-gaap:DebtCurrent
Finance lease, liability, noncurrent, statement of financial position [extensible list]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations

LEASE ASSETS AND LIABILITIES Table 2 (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021	$ 13,137
2022	12,419
2023	11,170
2024	10,294
2025	8,154
Thereafter	53,288
Total lease payments	108,462
Less: Interest	22,673
Present value of lease liability	85,789	$ 80,499
Finance Lease, Liability, Payment, Due [Abstract]
2021	5,907
2022	5,231
2023	5,102
2024	4,622
2025	3,898
Thereafter	56,079
Total lease payments	80,839
Less: Interest	22,762
Present value of lease liabilities	$ 58,077	$ 59,992

LEASE ASSETS AND LIABILITIES Table 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 16,814	$ 29,167
Amortization of right-of-use assets	4,700	3,748
Interest expense on lease liability	2,201	2,212
Short-term lease cost	15,359	19,140
Variable lease cost	8,653	6,990
Total lease cost	$ 47,727	$ 61,257

LEASE ASSETS AND LIABILITIES Narrative 3 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Leases [Abstract]
Operating Leases, Rent Expense, Net	$ 42.9

LEASE ASSETS AND LIABILITIES Table 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Leases [Abstract]
Cash outflows from operating activities	$ 14,487	$ 27,567
Right-of-use assets obtained in exchange for lease liabilities	$ 20,830	$ 2,153
Weighted-average remaining lease term (in years)	13 years	15 years
Weighted-average discount rate	3.20%	3.60%
Finance Leases [Abstract]
Cash outflows from operating activities	$ 2,208	$ 2,027
Cash outflows from financing activities	4,981	3,700
Right-of-use assets obtained in exchange for lease liabilities	$ 3,077	$ 4,430
Weighted-average remaining lease term (in years)	19 years	20 years
Weighted-average discount rate	3.70%	3.70%

LEASE ASSETS AND LIABILITIES Narrative 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2017
Lessor, Lease, Description [Line Items]
Lessor, operating lease, term of contract			10 years
Lessor, operating lease, payments to be received	$ 234,800
Service revenues [Member]
Lessor, Lease, Description [Line Items]
Operating lease, lease income	$ 41,300	$ 40,800

LEASE ASSETS AND LIABILITIES Table 5 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lease storage assets, at cost	$ 241,664,000	$ 238,204,000
Less accumulated depreciation	130,217,000	121,545,000
Lease storage assets, net	$ 111,447,000	$ 116,659,000
Estimated useful life	30 years

DERIVATIVES AND FAIR VALUE MEASUREMENTS Narrative 1 (Details) - USD ($) $ in Millions		1 Months Ended
	May 31, 2020	Jun. 30, 2020	May 31, 2020	Apr. 30, 2018	Apr. 15, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Cash paid for termination of interest rate swaps		$ 49.2
Cash received from termination of interest rate swaps				$ 8.0
Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swaps interest rate received			received a rate based on the three-month USD LIBOR
Interest rate swaps \| Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of forward-starting interest rate swaps terminated	$ 250.0			$ 350.0
7.65% senior notes
Derivative Instruments, Gain (Loss) [Line Items]
Long-term debt, rate					7.65%

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 1 - Fair Value of Unwound Interest Rate Swap Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Portion of Long-Term Debt [Member]
Derivatives, Fair Value
Fair market value of unwound fixed-to-floating interest rate swaps	$ 0	$ 2,755
Long-Term Debt, Less Current Portion [Member]
Derivatives, Fair Value
Fair market value of unwound fixed-to-floating interest rate swaps	1,363	2,568
Accumulated Other Comprehensive Income (Loss) [Member]
Derivatives, Fair Value
Fair market value of unwound forward starting interest rate swaps	$ (42,150)	$ 3,045

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 2 - Impact of Derivatives on Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to be reclassified during next 12 months, forward-starting interest rate swaps	$ (5,400)
Interest rate swaps \| Other comprehensive income
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss) on derivative	(30,291)	$ (19,045)	$ 17,912
Interest rate swaps \| Interest expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from AOCI into interest expense, net	$ (4,265)	$ (3,814)	$ (5,499)

DERIVATIVES AND FAIR VALUE MEASUREMENTS Narrative 2 - Fair Values of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value
Liability Derivatives	$ 0	$ (19,169)
Interest rate swaps \| Cash Flow Hedges
Derivatives, Fair Value
Derivative, notional amount		250,000
Level 2 [Member] \| Interest rate swaps \| Designated as Hedging Instrument [Member] \| Other Current Liabilities [Member]
Derivatives, Fair Value
Liability Derivatives		$ (19,200)

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 3 (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value, long-term debt	$ 3,799,378	$ 3,442,001
Long-term debt, including current portion and excluding finance leases	$ 3,539,258	$ 3,331,839

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 1 (Details) - USD ($) $ / shares in Units, $ in Thousands			9 Months Ended	12 Months Ended
	Jul. 13, 2018	Jun. 29, 2018	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Proceeds from issuance of Series D preferred units				$ 0	$ 0	$ 590,000
Series D preferred units outstanding				23,246,650	23,246,650
Series D Preferred Limited Partner [Member]
Class of Stock [Line Items]
Proceeds from issuance of Series D preferred units	$ 190,000	$ 400,000	$ 590,000
Series D preferred units outstanding			23,246,650
Units issued, price per unit	$ 25.38	$ 25.38
Issuance of preferred units (temporary equity) (in units)	7,486,209	15,760,441
Net proceeds from issuance of Series D preferred units		$ 370,700	$ 555,800			$ 555,797
Transaction fee percentage			3.50%
Transaction fee			$ 20,700
Equity issuance costs			$ 13,500

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 2 (Details) - Series D Preferred Limited Partner [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Required amount of per unit cash dividends to permit dividend paid in kind		$ 0.635
Unpaid dividend penalty, per unit dividend increase		$ 0.048
Unpaid dividend penalty, preferred stock, conversion basis		if we fail to pay in full any Series D Preferred Unit distribution amount for three consecutive distribution periods, then until we pay such distributions in full: (i) each holder of the Series D Preferred Units may elect to convert its Series D Preferred Units into common units on a one-for-one basis, plus any unpaid Series D distributions
Unpaid dividend penalty, minimum amount of acquisitions or asset sales requiring consent		$ 50.0
Preferred Stock, Distributions, Period - June 29, 2018 to June 28, 2020 [Member]
Class of Stock [Line Items]
Preferred units distribution percentage		9.75%
Preferred stock, dividend rate, amount per annum		$ 57.6
Cash distributions per unit applicable to limited partners		$ 0.619
Preferred Stock, Distributions, Period - June 29, 2020 to June 28, 2023 [Member]
Class of Stock [Line Items]
Preferred units distribution percentage		10.75%
Preferred stock, dividend rate, amount per annum		$ 63.4
Cash distributions per unit applicable to limited partners		$ 0.682
Preferred Stock, Distributions, Period - June 29, 2023 and thereafter [Member]
Class of Stock [Line Items]
Preferred unit, distribution payment rate, variable description		the greater of 13.75%, or $81.1 million, per annum ($0.872 per unit per distribution period) or the distribution per common unit thereafter
Minimum [Member] \| Preferred Stock, Distributions, Period - June 29, 2023 and thereafter [Member]
Class of Stock [Line Items]
Preferred units distribution percentage		13.75%
Preferred stock, dividend rate, amount per annum		$ 81.1
Cash distributions per unit applicable to limited partners		$ 0.872
Subsequent Event [Member]
Class of Stock [Line Items]
Cash distributions per unit applicable to limited partners	$ 0.682

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 3 (Details) - Series D Preferred Limited Partner [Member] $ in Millions		12 Months Ended
	Jul. 20, 2018	Dec. 31, 2020 USD ($)
Class of Stock [Line Items]
Convertible preferred units, terms of redemption		The Partnership may redeem all or any portion of the Series D Preferred Units, in an amount not less than $50.0 million for cash at a redemption price equal to, as applicable: (i) $31.73 per Series D Preferred Unit at any time on or after June 29, 2023 but prior to June 29, 2024; (ii) $30.46 per Series D Preferred Unit at any time on or after June 29, 2024 but prior to June 29, 2025; (iii) $29.19 per Series D Preferred Unit at any time on or after June 29, 2025; plus, in each case, the sum of any unpaid distributions on the applicable Series D Preferred Unit plus the distributions prorated for the number of days elapsed (not to exceed 90) in the period of redemption (Series D Partial Period Distributions). The holders have the option to convert the units prior to such redemption as discussed above. Additionally, at any time on or after June 29, 2028, each holder of Series D Preferred Units will have the right to require the Partnership to redeem all of the Series D Preferred Units held by such holder at a redemption price equal to $29.19 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions. If a holder of Series D Preferred Units exercises its redemption right, the Partnership may elect to pay up to 50% of such amount in common units (which shall be valued at 93% of a volume-weighted average trading price of the common units); provided, that the common units to be issued do not, in the aggregate, exceed 15% of NuStar Energy’s common equity market capitalization at the time.
Minimum conversion amount		$ 50.0
Maximum number of days within a partial distribution period		90
Convertible preferred units, terms of conversion, change of control		convert its Series D Preferred Units into common units on a one-for-one basis, plus any unpaid Series D distributions
Change of control redemption amount		the sum of (a) $29.82 per Series D Preferred Unit plus (b) any unpaid Series D distributions plus (c) the applicable distribution amount for the distribution periods ending after the change of control event and prior to (but including) the fourth anniversary of the Initial Closing
Temporary equity, accounting treatment		The Series D Preferred Units include redemption provisions at the option of the holders of the Series D Preferred Units and upon a Series D Change of Control (as defined in the partnership agreement), which are outside the Partnership’s control. Therefore, the Series D Preferred Units are presented in the mezzanine section of the consolidated balance sheets. The Series D Preferred Units have been recorded at their issuance date fair value, net of issuance costs. We reassess the presentation of the Series D Preferred Units in our consolidated balance sheets on a quarterly basis. The Series D Preferred Units are subject to accretion from their carrying value at the issuance date to the redemption value, which is based on the redemption right of the Series D Preferred Unit holders that may be exercised at any time on or after June 29, 2028, using the effective interest method over a period of ten years. In the calculation of net income per unit, the accretion is treated in the same manner as a distribution and deducted from net income to arrive at net income attributable to common units.
Accretion period	10 years
Preferred Stock, Conversion, Period - June 29, 2020 and thereafter [Member]
Class of Stock [Line Items]
Convertible preferred units, terms of conversion		Each holder of Series D Preferred Units may convert all or any portion of its Series D Preferred Units into common units on a one-for-one basis (plus any unpaid Series D distributions), subject to anti-dilution adjustments, at any time, but not more than once per quarter, so long as any conversion is for at least $50.0 million based on the Series D Preferred Unit Purchase Price (or such lesser amount representing all of a holder’s Series D Preferred Units).
Preferred Stock, Issuer Redemption Option, Period - June 29, 2023 to June 28, 2024 [Member]
Class of Stock [Line Items]
Temporary equity redemption price per unit		$31.73 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions
Preferred Stock, Issuer Redemption Option, Period - June 29, 2023 and thereafter [Member]
Class of Stock [Line Items]
Minimum redemption amount		$ 50.0
Preferred Stock, Holder Redemption Option, Period - June 29, 2028 and thereafter [Member]
Class of Stock [Line Items]
Temporary equity redemption price per unit		$29.19 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions
Percentage of redemption amount that may be paid in common limited partner units		50.00%
Volume-weighted average trading price percentage of common limited partner units		93.00%
Common limited partners' equity market capitalization, maximum allowable percentage		15.00%
Preferred Stock, Issuer Redemption Option, Period - June 29, 2024 to June 28, 2025 [Member]
Class of Stock [Line Items]
Temporary equity redemption price per unit		$30.46 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions
Preferred Stock, Issuer Redemption Option, Period - June 29, 2025 and thereafter [Member]
Class of Stock [Line Items]
Temporary equity redemption price per unit		$29.19 per Series D Preferred Unit plus any unpaid Series D distributions plus the Series D Partial Period Distributions

PARTNERS' EQUITY Narrative 1 (Details)	6 Months Ended
PARTNERS' EQUITY Narrative 1 (Details)	Jun. 30, 2018
Partners' Capital Notes [Abstract]
General partner ownership interest	2.00%

PARTNERS' EQUITY Table 1 - Preferred Units (Details) - USD ($)				12 Months Ended
	Nov. 30, 2017	Apr. 28, 2017	Nov. 25, 2016	Dec. 31, 2020
Series A Preferred Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)			9,060,000
Units issued, price per unit			$ 25.00
Preferred units liquidation preference			$ 25.00
Preferred units distribution percentage, fixed			8.50%
Per unit distribution, fixed, per annum			$ 2.125
Preferred stock, dividend rate, amount per annum				$ 19,252
Preferred unit, distribution payment rate, variable description			Three-month LIBOR plus 6.766%
Preferred units, description				We may redeem any of our outstanding Series A, B and C Preferred Units at any time on or after the optional redemption date set forth above for each series of the Series A, B and C Preferred Units, in whole or in part, at a redemption price of $25.00 per unit plus an amount equal to all accumulated and unpaid distributions to, but not including, the date of redemption, whether or not declared. We may also redeem the Series A, B and C Preferred Units upon the occurrence of certain rating events or a change of control as defined in our partnership agreement. In the case of the latter instance, if we choose not to redeem the Series A, B and C Preferred Units, those preferred unitholders may have the ability to convert their Series A, B and C Preferred Units to common units at the then applicable conversion rate. Holders of the Series A, B and C Preferred Units have no voting rights except for certain exceptions set forth in our partnership agreement.
Series B Preferred Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)		15,400,000
Units issued, price per unit		$ 25.00
Preferred units liquidation preference		$ 25.00
Preferred units distribution percentage, fixed		7.625%
Per unit distribution, fixed, per annum		$ 1.90625
Preferred stock, dividend rate, amount per annum				$ 29,357
Preferred unit, distribution payment rate, variable description		Three-month LIBOR plus 5.643%
Preferred units, description				We may redeem any of our outstanding Series A, B and C Preferred Units at any time on or after the optional redemption date set forth above for each series of the Series A, B and C Preferred Units, in whole or in part, at a redemption price of $25.00 per unit plus an amount equal to all accumulated and unpaid distributions to, but not including, the date of redemption, whether or not declared. We may also redeem the Series A, B and C Preferred Units upon the occurrence of certain rating events or a change of control as defined in our partnership agreement. In the case of the latter instance, if we choose not to redeem the Series A, B and C Preferred Units, those preferred unitholders may have the ability to convert their Series A, B and C Preferred Units to common units at the then applicable conversion rate. Holders of the Series A, B and C Preferred Units have no voting rights except for certain exceptions set forth in our partnership agreement.
Series C Preferred Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)	6,900,000
Units issued, price per unit	$ 25.00
Preferred units liquidation preference	$ 25.00
Preferred units distribution percentage, fixed	9.00%
Per unit distribution, fixed, per annum	$ 2.25
Preferred stock, dividend rate, amount per annum				$ 15,525
Preferred unit, distribution payment rate, variable description	Three-month LIBOR plus 6.88%
Preferred units, description				We may redeem any of our outstanding Series A, B and C Preferred Units at any time on or after the optional redemption date set forth above for each series of the Series A, B and C Preferred Units, in whole or in part, at a redemption price of $25.00 per unit plus an amount equal to all accumulated and unpaid distributions to, but not including, the date of redemption, whether or not declared. We may also redeem the Series A, B and C Preferred Units upon the occurrence of certain rating events or a change of control as defined in our partnership agreement. In the case of the latter instance, if we choose not to redeem the Series A, B and C Preferred Units, those preferred unitholders may have the ability to convert their Series A, B and C Preferred Units to common units at the then applicable conversion rate. Holders of the Series A, B and C Preferred Units have no voting rights except for certain exceptions set forth in our partnership agreement.

PARTNERS' EQUITY Narrative 2 (Details) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended	9 Months Ended	12 Months Ended
	Nov. 26, 2019	Jun. 29, 2018	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Proceeds from issuance of common units, including contributions from general partner	$ 15,000				$ 0	$ 15,000	$ 10,204
Proceeds from common unit issuance including general partner contribution		$ 10,200
General partner ownership interest			2.00%
Common Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)	527,426	413,736			0	527,426	413,736
Units issued, price per unit	$ 28.44	$ 24.17
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued				13,400,000	0	0	13,409,593
General Partner [Member]
Class of Stock [Line Items]
Proceeds from general partner contribution				$ 200
General partner ownership interest			2.00%

PARTNERS' EQUITY Table 2 - Balance of and Changes in Common Units Outstanding (Details) - shares			9 Months Ended	12 Months Ended
	Nov. 26, 2019	Jun. 29, 2018	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Limited partners common units outstanding (in units)				109,468,127	108,527,806
Common Limited Partner [Member]
Class of Stock [Line Items]
Limited partners common units outstanding (in units)				109,468,127	108,527,806	107,225,156	93,176,683
Issuance of units (units)	527,426	413,736		0	527,426	413,736
Unit-based compensation (units)				940,321	775,224	225,144
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued			13,400,000	0	0	13,409,593

PARTNERS' EQUITY Narrative 3 (Details)	12 Months Ended
PARTNERS' EQUITY Narrative 3 (Details)	Dec. 31, 2020
Partners' Capital Notes [Abstract]
Percent of available cash distributed	100.00%
Number of days within which distribution is paid to common unitholders	45

PARTNERS' EQUITY Table 3 - Cash Distributions Declared - Common Limited Partners (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Distribution Made to Limited Partner [Line Items]
Common limited partners' distribution, per unit	$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 1.60	$ 2.40	$ 2.40
Common limited partners' distribution	$ 43,787	$ 43,678	$ 43,678	$ 43,730	$ 174,873	$ 259,136	$ 248,705
Common Limited Partner [Member]
Distribution Made to Limited Partner [Line Items]
Distribution date of record (distribution earned)	Feb. 08, 2021	Nov. 06, 2020	Aug. 07, 2020	May 11, 2020
Distribution payment date	Feb. 12, 2021	Nov. 13, 2020	Aug. 13, 2020	May 15, 2020

PARTNERS' EQUITY Narrative 4 (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Distribution Made to Limited Partner [Line Items]
Cash distributions to general partner
General partner interest			$ 1,100
General Partner [Member]
Distribution Made to Limited Partner [Line Items]
Cash distributions to general partner	$ 0		$ 14,379

PARTNERS' EQUITY Table 4 - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (67,896)
Other comprehensive income (loss)	(28,760)	$ (13,018)	$ 30,049
Ending balance	(96,656)	(67,896)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(43,772)	(47,299)	(51,603)
Other comprehensive income (loss) before reclassifications	1,410	3,527	(13,880)
Other			60
Other comprehensive income (loss)	1,410	3,527	4,304
Ending balance	(42,362)	(43,772)	(47,299)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(16,124)	(893)	(24,304)
Other comprehensive income (loss) before reclassifications	(30,291)	(19,045)	17,912
Net loss (gain) reclassified from AOCI			0
Other			0
Other comprehensive income (loss)	(26,026)	(15,231)	23,411
Ending balance	(42,150)	(16,124)	(893)
Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(8,000)	(6,686)	(9,020)
Other comprehensive income (loss) before reclassifications	(2,924)	1,000	3,282
Net loss (gain) reclassified from AOCI			0
Other			(134)
Other comprehensive income (loss)	(4,144)	(1,314)	2,334
Ending balance	(12,144)	(8,000)	(6,686)
Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(67,896)	(54,878)	(84,927)
Other comprehensive income (loss) before reclassifications	(31,805)	(14,518)	7,314
Other			(74)
Other comprehensive income (loss)	(28,760)	(13,018)	30,049
Ending balance	(96,656)	(67,896)	(54,878)
Interest expense, net \| Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	0	0	0
Interest expense, net \| Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	4,265	3,814	5,499
Interest expense, net \| Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	0	0	0
Interest expense, net \| Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	4,265	3,814	5,499
Pension Plan [Member] \| Other Income [Member] \| Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	0	0	0
Pension Plan [Member] \| Other Income [Member] \| Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	0	0	0
Pension Plan [Member] \| Other Income [Member] \| Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	(1,220)	(2,314)	(814)
Pension Plan [Member] \| Other Income [Member] \| Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	$ (1,220)	$ (2,314)	(814)
Sale of U.K. and Amsterdam Operations [Member] \| Other Income [Member] \| Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			18,124
Sale of U.K. and Amsterdam Operations [Member] \| Other Income [Member] \| Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			$ 18,124

NET (LOSS) INCOME PER COMMON UNIT Table - Net (Loss) Income per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss)					$ (198,983)	$ (105,693)	$ 205,794
Distributions to preferred limited partners					(124,882)	(121,693)	(92,540)
Distributions to general partner					0	0	(1,141)
Distributions to common limited partners	$ (43,787)	$ (43,678)	$ (43,678)	$ (43,730)	(174,873)	(259,136)	(248,705)
Distribution equivalent rights to restricted units					(2,093)	(2,659)	(2,045)
Distributions in excess of (loss) income					(500,831)	(489,181)	(138,637)
Distributions to common limited partners	$ 43,787	$ 43,678	$ 43,678	$ 43,730	174,873	259,136	248,705
Allocation of distributions in excess of (loss) income					(500,831)	(489,181)	(138,659)
Series D Preferred Unit accretion (refer to Note 18)					(17,626)	(18,085)	(8,195)
Loss to common unitholders attributable to the Merger (refer to Note 5)					0	0	(377,079)
Net loss attributable to common units					$ (343,584)	$ (248,130)	$ (275,228)
Basic weighted-average common units outstanding					109,155,117	107,789,030	99,490,495
Basic weighted-average common units outstanding					109,155,117	107,789,030	99,490,495
Effect of dilutive potential common units					0	65,669	40,677
Diluted weighted-average common units outstanding					109,155,117	107,854,699	99,531,172
Basic net (loss) income per common unit					$ (3.15)	$ (2.30)	$ (2.77)
Diluted net income (loss) per common unit					$ (3.15)	$ (2.30)	$ (2.77)

SUPPLEMENTAL CASH FLOW INFORMATION Table 1 - Changes in Current Assets and Current Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Accounts receivable	$ 14,589	$ (23,480)	$ 22,482
Receivable from related party	0	0	160
Inventories	1,340	(866)	3,819
Prepaid and other current assets	(3,326)	(5,103)	3,694
Accounts payable	(25,455)	8,068	8,003
Accrued interest payable	12,922	1,632	(4,279)
Accrued liabilities	7,886	(19,740)	39,862
Taxes other than income tax	3,972	(5,276)	4,521
Changes in current assets and current liabilities	$ 11,928	$ (44,765)	$ 78,262

SUPPLEMENTAL CASH FLOW INFORMATION Table 2 - Cash Flows Related to Interest and Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amount capitalized	$ 204,511	$ 176,859	$ 183,078
Cash paid for income taxes, net of tax refunds received	$ 3,260	$ 6,817	$ 8,535

SUPPLEMENTAL CASH FLOW INFORMATION Table 3 - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 153,625	$ 16,192
Cash, cash equivalents and restricted cash	162,426	24,980	$ 13,644	$ 24,292
Cash and Cash Equivalents [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	153,625	16,192
Other long-term assets, net
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, cash equivalents and restricted cash	$ 8,801	$ 8,788

EMPLOYEE BENEFIT PLANS Narrative 1 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Thrift Plan, description	The NuStar Thrift Plan (the Thrift Plan) is a qualified defined contribution plan that became effective June 26, 2006. Participation in the Thrift Plan is voluntary and open to substantially all our domestic employees upon their dates of hire. Thrift Plan participants can contribute from 1% up to 30% of their total annual compensation to the Thrift Plan in the form of pre-tax and/or after tax employee contributions. We make matching contributions in an amount equal to 100% of each participant’s employee contributions up to a maximum of 6% of the participant’s total annual compensation.
Thrift Plan matching contributions	$ 7.8	$ 7.6	$ 7.4
Benefit plan costs, international employees	$ 0.5	$ 0.9	$ 2.5
Pension Plan, description	The NuStar Pension Plan (the Pension Plan) is a qualified non-contributory defined benefit pension plan that provides eligible U.S. employees with retirement income as calculated under a cash balance formula. Under the cash balance formula, benefits are determined based on age, years of vesting service and interest credits, and employees become fully vested in their benefits upon attaining three years of vesting service. Prior to January 1, 2014, eligible employees were covered under either a cash balance formula or a final average pay formula (FAP). Effective January 1, 2014, the Pension Plan was amended to freeze the FAP benefits as of December 31, 2013, and going forward, all eligible employees are covered under the cash balance formula discussed above.

EMPLOYEE BENEFIT PLANS Table 1 - Changes in Benefit Obligation/Fair Value of Plan Assets/Funded Status/Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Pension Plan [Member]
Change in benefit obligation:
Benefit obligation, January 1	$ 167,257	$ 141,833
Service cost	9,174	9,549	$ 9,621
Interest cost	4,693	5,480	4,824
Benefits paid	(9,520)	(7,109)
Participant contributions	0	0
Actuarial loss (gain)	15,081	17,504
Benefit obligation, December 31	186,685	167,257	141,833
Change in plan assets:
Plan assets at fair value, January 1	159,036	126,949
Actual return on plan assets	21,758	28,064
Employer contributions	11,453	11,132
Benefits paid	(9,520)	(7,109)
Participant contributions	0	0
Plan assets at fair value, December 31	182,727	159,036	126,949
Reconciliation of funded status:
Fair value of plan assets at December 31	182,727	126,949	126,949	$ 182,727	$ 159,036
Less: Benefit obligation at December 31	186,685	141,833	141,833	186,685	167,257
Funded status at December 31				(3,958)	(8,221)
Amounts recognized in the consolidated balance sheets:
Accrued liabilities				(382)	(303)
Other long-term liabilities				(3,576)	(7,918)
Net pension liability				(3,958)	(8,221)
Accumulated benefit obligation for the Pension Plans				181,263	164,183
Pension Plan [Member] \| Excess Pension Plan [Member]
Change in plan assets:
Plan assets at fair value, January 1	0
Plan assets at fair value, December 31	0	0
Reconciliation of funded status:
Fair value of plan assets at December 31	0	0		0	0
Amounts recognized in the consolidated balance sheets:
Accumulated benefit obligation for the Pension Plans				3,800	3,700
Pension Plan [Member] \| Excess Pension Plan and Other Postretirement Benefit Plans
Change in plan assets:
Plan assets at fair value, January 1	0
Plan assets at fair value, December 31	0	0
Reconciliation of funded status:
Fair value of plan assets at December 31	0	0		0	0
Other Postretirement Benefit Plans [Member]
Change in benefit obligation:
Benefit obligation, January 1	13,196	10,908
Service cost	529	431	504
Interest cost	399	453	429
Benefits paid	(281)	(217)
Participant contributions	44	62
Actuarial loss (gain)	793	1,559
Benefit obligation, December 31	14,680	13,196	10,908
Change in plan assets:
Plan assets at fair value, January 1	0	0
Actual return on plan assets	0	0
Employer contributions	237	155
Benefits paid	(281)	(217)
Participant contributions	44	62
Plan assets at fair value, December 31	0	0	0
Reconciliation of funded status:
Fair value of plan assets at December 31	0	0	0	0	0
Less: Benefit obligation at December 31	$ 14,680	$ 10,908	$ 10,908	14,680	13,196
Funded status at December 31				(14,680)	(13,196)
Amounts recognized in the consolidated balance sheets:
Accrued liabilities				(352)	(368)
Other long-term liabilities				(14,328)	(12,828)
Net pension liability				(14,680)	(13,196)
Accumulated benefit obligation for the Pension Plans				$ 14,680	$ 13,196

EMPLOYEE BENEFIT PLANS Narrative 2 (Details) - Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.84%	3.34%	4.40%
Fair value of plan assets	$ 182,727	$ 159,036	$ 126,949
Accumulated benefit obligation for the Pension Plans	181,263	164,183
Excess Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Accumulated benefit obligation for the Pension Plans	$ 3,800	$ 3,700

- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References + Details

EMPLOYEE BENEFIT PLANS Table 2 - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, assumptions used in calculations description	We amortize prior service costs and credits on a straight-line basis over the average remaining service period of employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of prior service credit” in table above). We amortize the actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation or market-related value of plan assets (smoothed asset value) over the average remaining service period of active employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of net actuarial loss” in table above).
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9,174	$ 9,549	$ 9,621
Interest cost	4,693	5,480	4,824
Expected return on plan assets	(8,972)	(8,015)	(7,417)
Amortization of prior service credit	(2,057)	(2,057)	(2,057)
Amortization of net actuarial loss	1,845	846	2,174
Excess Pension Plan settlement	136	0	0
Net periodic benefit cost (income)	4,819	5,803	7,145
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	529	431	504
Interest cost	399	453	429
Expected return on plan assets	0	0	0
Amortization of prior service credit	(1,145)	(1,145)	(1,145)
Amortization of net actuarial loss	137	42	214
Excess Pension Plan settlement	0	0	0
Net periodic benefit cost (income)	$ (80)	$ (219)	$ 2

EMPLOYEE BENEFIT PLANS Table 3 - Adjustments to Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Income tax (expense) benefit	$ 28	$ 14	$ (94)
Total changes in other comprehensive income (loss)	(4,144)	(1,314)	2,334
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	(2,159)	2,545	1,049
Amortization of prior service credit	(2,057)	(2,057)	(2,057)
Amortization of net actuarial loss	1,845	846	2,174
Net (gain) loss reclassified into income	(212)	(1,211)	117
Reclassification of stranded tax effects	0	0	(74)
Income tax (expense) benefit	28	14	(69)
Total changes in other comprehensive income (loss)	(2,343)	1,348	1,023
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	(793)	(1,559)	2,267
Amortization of prior service credit	(1,145)	(1,145)	(1,145)
Amortization of net actuarial loss	137	42	214
Net (gain) loss reclassified into income	(1,008)	(1,103)	(931)
Reclassification of stranded tax effects	0	0	0
Income tax (expense) benefit	0	0	(25)
Total changes in other comprehensive income (loss)	$ (1,801)	$ (2,662)	$ 1,311

EMPLOYEE BENEFIT PLANS Table 4 - Amounts Recorded as a Component of Accumulated Other Comprehensive (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	$ (24,878)	$ (24,564)
Prior service credit	10,433	12,490
Deferred tax asset (liability)	118	90
Accumulated other comprehensive income (loss), net of tax	(14,327)	(11,984)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	(3,846)	(3,190)
Prior service credit	6,029	7,174
Deferred tax asset (liability)	0	0
Accumulated other comprehensive income (loss), net of tax	$ 2,183	$ 3,984

EMPLOYEE BENEFIT PLANS Narrative 3 (Details)	Dec. 31, 2020
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, target plan asset allocations	65.00%
Fixed income investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, target plan asset allocations	35.00%

EMPLOYEE BENEFIT PLANS Table 5 - Major Classes of Plan Assets Measured at Fair Value (Details) - Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 182,727	$ 159,036	$ 126,949
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77,870	66,299
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,857	92,737
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash equivalent securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,125	160
Cash equivalent securities [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,125	160
Cash equivalent securities [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash equivalent securities [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large cap equity fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,857	92,737
U.S. large cap equity fund [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. large cap equity fund [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,857	92,737
U.S. large cap equity fund [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International stock index fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,732	17,473
International stock index fund [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,732	17,473
International stock index fund [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
International stock index fund [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Bond market index fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,013	48,666
Bond market index fund [Member] \| Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,013	48,666
Bond market index fund [Member] \| Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Bond market index fund [Member] \| Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

EMPLOYEE BENEFIT PLANS Narrative 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan contributions	$ 11,453	$ 11,132
Estimated future employer contributions in next fiscal year	9,400
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan contributions	237	$ 155
Estimated future employer contributions in next fiscal year	$ 300

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References + Details

EMPLOYEE BENEFIT PLANS Table 6 - Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Pension Plan [Member]
Estimated Future Benefit Payments
2021	$ 9,771
2022	10,030
2023	10,329
2024	10,846
2025	11,558
2026-2030	61,321
Other Postretirement Benefit Plans [Member]
Estimated Future Benefit Payments
2021	352
2022	397
2023	451
2024	483
2025	529
2026-2030	$ 3,355

EMPLOYEE BENEFIT PLANS Table 7 - Assumptions - Benefit Obligations (Details)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.84%	3.34%	4.40%
Rate of compensation increase	3.51%	3.51%
Cash balance interest crediting rate	2.00%	2.00%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.83%	3.43%

EMPLOYEE BENEFIT PLANS Table 8 - Assumptions - Net Periodic Benefit Cost (Income) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.34%	4.40%	3.72%
Expected long-term rate of return on plan assets	6.50%	6.50%	6.50%
Rate of compensation increase	3.51%	3.51%	3.51%
Cash balance interest crediting rate	2.00%	2.90%	2.00%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.43%	4.53%	3.82%

EMPLOYEE BENEFIT PLANS Table 9 - Assumptions - Health Care Cost Trend Rates (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	6.84%	6.84%
Rate to which the cost trend rate was assumed to decrease (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2028	2028
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Cap on increase in the employer's cost	The cap on the increase in employer’s cost is 2.5% per year.

UNIT-BASED COMPENSATION Narrative 1 (Details) - shares	Dec. 31, 2020	Apr. 23, 2019	Jul. 20, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common unit conversion rate			55.00%
The 2019 LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, number of units authorized		2,500,000
Unit-based compensation, number of units available to be awarded	399,790

UNIT-BASED COMPENSATION Table 1 - Information for LTIP Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	2,441,003	1,456,296	1,277,480
Compensation expense	$ 12,185	$ 38,035	$ 30,699
Restricted units, domestic employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	2,235,125	1,223,143	1,028,484	736,746
Compensation expense	$ 10,205	$ 9,437	$ 8,233
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	98,769	61,349	59,752	27,097
Compensation expense	$ 631	$ 774	$ 524
Restricted units, international employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	19,987	10,243	30,918
Compensation expense	$ 58	$ 711	$ 1,158
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	57,448	74,439	80,690	38,865
Compensation expense	$ 1,291	$ 4,172	$ 1,889
Performance units awarded and outstanding	87,122	161,561	158,326	80,961
Unit Awards[Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0	$ 22,941	$ 18,895
Performance units awarded and outstanding	0	0	0

UNIT-BASED COMPENSATION Narrative 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash payments made in connection with DERs	$ 2,093	$ 2,659	$ 2,045
Restricted units, domestic employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, vesting period	5 years
Unit-based awards, granted (units)			518,282
Unit-based awards, vested (units)			235,746
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, vesting period	3 years
Unit-based awards, granted (units)			34,303
Unit-based awards, vested (units)			20,563
Restricted units, international employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, vesting period	3 years
Unit-based awards, granted (units)	14,581
Unit-based awards, vested (units)	4,837

UNIT-BASED COMPENSATION Table 2 - Restricted Unit Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,456,296	1,277,480
Unit-based awards, ending balance (units)	2,441,003	1,456,296	1,277,480
Restricted units, domestic employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,223,143	1,028,484	736,746
Unit based awards, converted (units)			53,447
Unit-based awards, granted (units)			518,282
Unit-based awards, vested (units)			(235,746)
Unit-based awards, forfeited (units)			(44,245)
Unit-based awards, ending balance (units)	2,235,125	1,223,143	1,028,484
Weighted-average grant date fair value (per unit), period start		$ 29.47	$ 35.95
Weighted-average grant date fair value, converted (per unit)			24.99
Weighted-average grant date fair value (per unit), granted			24.07
Weighted-average grant date fair value (per unit), vested			35.12
Weighted-average grant date fair value (per unit), forfeited			36.05
Weighted-average grant date fair value (per unit), period end			$ 29.47
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	61,349	59,752	27,097
Unit based awards, converted (units)			18,915
Unit-based awards, granted (units)			34,303
Unit-based awards, vested (units)			(20,563)
Unit-based awards, forfeited (units)			0
Unit-based awards, adoption of accounting pronouncement (units)		59,752
Unit-based awards, adoption of accounting pronouncement, NEDS MtM (units)				(59,752)
Unit-based awards, ending balance (units)	98,769	61,349	59,752
Weighted-average grant date fair value, adoption of accounting pronouncement (per unit)		$ 20.93
Restricted units, employees and non-employee directors (NEDs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,284,492
Unit-based awards, granted (units)	1,454,998	596,881
Unit-based awards, vested (units)	(374,847)	(328,386)
Unit-based awards, forfeited (units)	(30,749)	(72,239)
Unit-based awards, ending balance (units)	2,333,894	1,284,492
Weighted-average grant date fair value (per unit), period start	$ 27.48
Weighted-average grant date fair value (per unit), granted	12.10	$ 26.46
Weighted-average grant date fair value (per unit), vested	28.47	30.11
Weighted-average grant date fair value (per unit), forfeited	26.75	28.05
Weighted-average grant date fair value (per unit), period end	$ 17.70	$ 27.48

UNIT-BASED COMPENSATION Narrative 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted units that vested during the period	$ 4,600	$ 9,300	$ 6,200
Units issued to satisfy award vestings, net of tax (units)	275,146	242,199	189,399
Unrecognized compensation cost	$ 38,100
Compensation cost not yet recognized, period for recognition	3 years 9 months 18 days
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted units that vested during the period	$ 4,200	$ 2,100
Units issued to satisfy award vestings, net of tax (units)	93,440	50,054
Unit-based compensation, description of performance units	Performance awards are issued to certain of our key employees and represent either rights to receive our common units or cash upon achieving performance measures for the performance period established by the NuStar GP, LLC Compensation Committee. Achievement of the performance measures determines the rate at which the performance awards convert into our common units or cash, which ranges from zero to 200% for certain awards.
Unit-based compensation, terms of performance units	Performance awards vest in three annual increments (tranches), based upon our achievement of the performance measures set by the Compensation Committee during the performance periods that end on December 31 of each applicable year.
Unit-based compensation, requisite service period	1 year

UNIT-BASED COMPENSATION Table 3 - Summary of Performance Units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,456,296	1,277,480
Unit-based awards, ending balance (units)	2,441,003	1,456,296	1,277,480
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units awarded and outstanding, period start	161,561	158,326	80,961
Performance units awarded	0	95,969	116,230
Performance units forfeited		(12,044)	(38,865)
Unit-based awards, vested (units)	(147,390)	(80,690)	0
Performance awards, performance adjustment (units)	72,951
Performance units awarded and outstanding, period end	87,122	161,561	158,326
Unit-based awards, beginning balance (units)	74,439	80,690	38,865
Unit-based awards, granted (units)	57,448	74,439	80,690
Unit-based awards, forfeited (units)		0	(38,865)
Unit-based awards, ending balance (units)	57,448	74,439	80,690
Weighted-average grant date fair value (per unit), period start	$ 28.01	$ 23.43	$ 50.04
Weighted-average grant date fair value (per unit), granted	13.21	28.01	23.43
Weighted-average grant date fair value (per unit), forfeited		0	50.04
Weighted-average grant date fair value (per unit), vested	28.01	23.43
Weighted-average grant date fair value (per unit), performance adjustment	28.01
Weighted-average grant date fair value (per unit), period end	$ 13.21	$ 28.01	$ 23.43
Performance target attained	198.00%

UNIT-BASED COMPENSATION Narrative 4 (Details) - USD ($)		12 Months Ended
UNIT-BASED COMPENSATION Narrative 4 (Details) - USD ($)	Feb. 01, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted units that vested during the period		$ 4,200,000	$ 2,100,000
Units issued to satisfy award vestings, net of tax (units)		93,440	50,054
Unit-based awards, vested (units)		(147,390)	(80,690)	0
Performance cash awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance cash awards granted, amount		$ 2,200,000
Performance cash awards \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units issued in connection with performance cash awards	58,070

UNIT-BASED COMPENSATION Table 4 - Unit Awards (Details) - Share-based Payment Arrangement [Member] - USD ($) $ in Thousands	1 Months Ended		2 Months Ended	12 Months Ended
	Feb. 28, 2019	Jul. 31, 2018	Mar. 31, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, description of performance units				Unit awards are equity-classified awards of fully vested common units. We accrued compensation expense in 2019 and 2018 that was paid in unit awards in the first quarter of the subsequent year. We base the number of unit awards granted on the fair value of the common units at the grant date.
Weighted-average grant date fair value, granted	$ 17,537	$ 1,358	$ 22,941
Unit-based awards, granted (units)	704,886	55,133	834,224
Common Limited Partner [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of units (units)	482,971	35,745	571,735

INCOME TAXES Table 1 - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S.	$ 36	$ 3,741	$ 4,515
Foreign	2,415	1,489	4,658
Foreign withholding tax	0	101	192
Total current	2,451	5,331	9,365
Deferred:
U.S.	300	(490)	1,403
Foreign	(621)	(168)	394
Foreign withholding tax	533	182	246
Total deferred	212	(476)	2,043
Less: amounts reported in discontinued operations	0	101	1,251
Income tax expense	$ 2,663	$ 4,754	$ 10,157

INCOME TAXES Table 2 - Tax Effects of Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax assets:
Net operating losses	$ 18,459	$ 26,081
Employee benefits	134	372
Environmental and legal reserves	105	267
Capital loss	10,813	3,870
Other	834	693
Total deferred income tax assets	30,345	31,283
Less: Valuation allowance	(28,211)	(17,743)
Net deferred income tax assets	2,134	13,540
Deferred income tax liabilities:
Property, plant and equipment	(13,772)	(25,169)
Foreign withholding tax	(1,002)	(433)
Other	(371)	(365)
Total deferred income tax liabilities	(15,145)	(25,967)
Net deferred income tax liability	(13,011)	(12,427)
Reported on the Consolidated Balance Sheets as:
Deferred income tax liability	$ (13,011)	$ (12,427)

INCOME TAXES Narrative 1 - Operating Loss Carryforwards - Valuation Allowarnces (Details) $ in Millions	Dec. 31, 2020 USD ($)
U.S. [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 58.0
U.S. [Member] \| After December 31, 2017
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	4.9
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 21.0

INCOME TAXES Narrative 2 - Capital Loss Carryforwards (Details) - U.S. [Member] $ in Millions	Dec. 31, 2020 USD ($)
Capital Loss Carryforwards [Line Items]
Capital loss carryforward	$ 51.5
Capital loss carryforward, subject to limitations	$ 17.7

INCOME TAXES Narrative 3 - Valuation Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 28,211	$ 17,743
U.S. [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	10,000
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 500

SEGMENT INFORMATION Table 1 - Results of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Revenues	$ 1,481,564	$ 1,498,021	$ 1,520,262
Depreciation, Depletion and Amortization [Abstract]
Other depreciation and amortization expense	8,625	8,360	8,604
Total depreciation and amortization expense	285,101	272,924	255,892
Operating income (loss):
General and administrative expenses	102,716	107,855	100,067
Other depreciation and amortization expense	8,625	8,360	8,604
Operating income (loss)	209,102	390,916	335,728
Pipeline Segment
Revenues:
Revenues	718,823	701,830	611,065
Storage Segment
Revenues:
Revenues	494,442	454,001	443,588
Storage Segment \| Third Party Revenue [Member]
Revenues:
Revenues	494,396	453,976	443,546
Storage Segment \| Intersegment revenue [Member]
Revenues:
Revenues	46	25	42
Fuels Marketing Segment
Revenues:
Revenues	268,345	342,215	465,651
Operating Segments [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense	276,476	264,564	247,288
Operating income (loss):
Operating income (loss)	320,443	507,131	444,399
Operating Segments [Member] \| Pipeline Segment
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense	177,384	166,991	153,943
Operating income (loss):
Operating income (loss)	118,429	332,480	272,695
Operating Segments [Member] \| Storage Segment
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense	99,092	97,573	93,345
Operating income (loss):
Operating income (loss)	189,781	154,105	155,708
Operating Segments [Member] \| Fuels Marketing Segment
Operating income (loss):
Operating income (loss)	12,233	20,578	15,964
Intersegment Eliminations [Member]
Revenues:
Revenues	(46)	(25)	(42)
Operating income (loss):
Operating income (loss)	0	(32)	32
Corporate, Non-Segment [Member]
Depreciation, Depletion and Amortization [Abstract]
Other depreciation and amortization expense	8,625	8,360	8,604
Operating income (loss):
General and administrative expenses	102,716	107,855	100,067
Other depreciation and amortization expense	$ 8,625	$ 8,360	$ 8,604

SEGMENT INFORMATION Table 2 - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues By Geographic Areas
Revenues	$ 1,481,564	$ 1,498,021	$ 1,520,262
United States
Revenues By Geographic Areas
Revenues	1,441,892	1,465,135	1,481,844
Foreign
Revenues By Geographic Areas
Revenues	$ 39,672	$ 32,886	$ 38,418

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details

SEGMENT INFORMATION Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Major Customer [Line Items]
Revenues	$ 1,481,564	$ 1,498,021	$ 1,520,262
Revenue Benchmark [Member] \| Valero Energy Corporation [Member]
Revenue, Major Customer [Line Items]
Largest customer percentage of revenue	20.00%	21.00%	20.00%
Revenues	$ 295,100	$ 307,200	$ 303,700

- Definition

+ References

+ Details

SEGMENT INFORMATION Table 3 - Property, Plant, and Equipment, Net, by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Long-Lived Assets By Geographic Areas
Long-lived assets	$ 3,957,512	$ 4,118,979
United States
Long-Lived Assets By Geographic Areas
Long-lived assets	3,837,550	4,000,647
Foreign
Long-Lived Assets By Geographic Areas
Long-lived assets	$ 119,962	$ 118,332

SEGMENT INFORMATION Table 4 - Assets by Reportable Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Segment Information
Total consolidated assets	$ 5,817,018	$ 6,185,992
Operating Segments [Member]
Segment Information
Total consolidated assets	5,538,642	5,998,715
Operating Segments [Member] \| Pipeline Segment
Segment Information
Total consolidated assets	3,609,508	3,884,819
Operating Segments [Member] \| Storage Segment
Segment Information
Total consolidated assets	1,897,167	2,082,832
Operating Segments [Member] \| Fuels Marketing Segment
Segment Information
Total consolidated assets	31,967	31,064
Corporate, Non-Segment [Member]
Segment Information
Total consolidated assets	$ 278,376	$ 187,277

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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+ Details

SEGMENT INFORMATION Table 5 - Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Information
Capital expenditures	$ 198,079	$ 533,568	$ 494,954
Corporate, Non-Segment [Member]
Segment Information
Capital expenditures	3,779	3,894	4,137
Pipeline Segment
Segment Information
Capital expenditures	122,512	387,702	288,035
Storage Segment
Segment Information
Capital expenditures	$ 71,788	141,972	202,782
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Segment Information
Capital expenditures, discontinued operations		$ 27,954	$ 114,811