NuStar Energy (NS) 10-K 27 Feb 20 2019 FY Annual report Financial data

DEI Document

DEI Document - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 28, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
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
Entity Shell Company	false
Entity Public Float			$ 2.7
Entity Partnership Units Outstanding		108,527,939
Entity Central Index Key	0001110805
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
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

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 16,192	$ 11,529
Accounts receivable, net of allowance for doubtful accounts of $72 and $9,412 as of December 31, 2019 and 2018, respectively	152,530	110,417
Inventories	12,393	8,434
Prepaid and other current assets	21,933	17,374
Assets held for sale	0	599,347
Total current assets	203,048	747,101
Property, plant and equipment, at cost	6,187,144	5,627,805
Accumulated depreciation and amortization	(2,068,165)	(1,853,003)
Property, plant and equipment, net	4,118,979	3,774,802
Intangible assets, net	681,632	733,056
Goodwill	1,005,853	1,005,853
Other long-term assets, net	176,480	88,328
Total assets	6,185,992	6,349,140
Current liabilities:
Accounts payable	109,834	103,122
Short-term debt and current portion of finance leases	10,046	18,500
Current portion of long-term debt	452,367	0
Accrued interest payable	37,925	36,293
Accrued liabilities	104,285	74,418
Taxes other than income tax	12,781	16,823
Income tax payable	4,325	4,445
Liabilities held for sale	0	69,834
Total current liabilities	731,563	323,435
Long-term debt, less current portion	2,934,918	3,111,996
Deferred income tax liability	12,427	12,428
Other long-term liabilities	148,939	79,558
Total liabilities	3,827,847	3,527,417
Commitments and contingencies (Note 16)
Series D preferred limited partners (23,246,650 preferred units outstanding as of December 31, 2019 and 2018) (Note 19)	581,935	563,992
Partners’ equity (Note 20):
Common limited partners (108,527,806 and 107,225,156 common units outstanding as of December 31, 2019 and 2018, respectively)	1,087,805	1,556,308
Accumulated other comprehensive loss	(67,896)	(54,878)
Total partners' equity	1,776,210	2,257,731
Total liabilities, mezzanine equity and partners’ equity	6,185,992	6,349,140
Series A Preferred Limited Partner [Member]
Partners’ equity (Note 20):
Preferred limited partners	218,307	218,307
Series B Preferred Limited Partner [Member]
Partners’ equity (Note 20):
Preferred limited partners	371,476	371,476
Series C Preferred Limited Partner [Member]
Partners’ equity (Note 20):
Preferred limited partners	$ 166,518	$ 166,518

CONSOLIDATED BALANCE SHEETS Non

CONSOLIDATED BALANCE SHEETS Non-Printing - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 72	$ 9,412
Series D preferred units outstanding	23,246,650	23,246,650
Limited partners common units outstanding (in units)	108,527,806	107,225,156
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 (LOS

CONSOLIDATED STATEMENTS OF (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenues	$ 1,498,021	$ 1,520,262	$ 1,444,772
Costs and expenses:
General and administrative expenses (excluding depreciation and amortization expense)	107,855	100,067	107,556
Other depreciation and amortization expense	8,360	8,604	8,435
Total costs and expenses	1,107,105	1,184,534	1,154,262
Operating income	390,916	335,728	290,510
Interest expense, net	(183,070)	(184,398)	(171,774)
Other income (expense), net	3,742	5,202	(68)
Income (loss) from continuing operations before income tax expense (benefit)	211,588	156,532	118,668
Income tax expense	4,754	10,157	7,773
Income (loss) from continuing operations, net of tax	206,834	146,375	110,895
Income (loss) from discontinued operations, net of tax	(312,527)	59,419	37,069
Net income (loss)	$ (105,693)	$ 205,794	$ 147,964
Basic net income (loss) per common unit (Note 21)
Continuing operations	$ 0.60	$ (3.34)	$ 0.23
Discontinued operations	(2.90)	0.57	0.41
Total net income (loss) per common unit	(2.30)	(2.77)	0.64
Diluted net income (loss) per common unit (Note 21)
Continuing operations	0.60	(3.34)	0.23
Discontinued operations	(2.90)	0.57	0.41
Total net income (loss) per common unit	$ (2.30)	$ (2.77)	$ 0.64
Basic weighted-average common units outstanding	107,789,030	99,490,495	88,825,964
Diluted weighted-average common units outstanding	107,854,699	99,531,172	88,825,964
Service [Member]
Revenues:
Total revenues	$ 1,148,167	$ 1,045,130	$ 955,446
Costs and expenses:
Operating expenses (excluding depreciation and amortization expense)	404,682	378,962	332,723
Depreciation and amortization expense	264,564	247,288	219,757
Total costs associated with service revenues/Cost of product sales	669,246	626,250	552,480
Product [Member]
Revenues:
Total revenues	349,854	475,132	489,326
Costs and expenses:
Total costs associated with service revenues/Cost of product sales	$ 321,644	$ 449,613	$ 485,791

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133	$ (105,693)	$ 205,794	$ 147,964
Other comprehensive income (loss):
Foreign currency translation adjustment									3,527	4,304	17,466
Net (loss) gain on pension and other postretirement benefit adjustments, net of income tax benefit (expense) of $14, ($94) and $184									(1,314)	2,334	(6,170)
Net (loss) gain on cash flow hedges									(15,231)	23,411	(2,046)
Total other comprehensive income (loss)									(13,018)	30,049	9,250
Comprehensive income (loss)									(118,711)	235,843	157,214
Income tax (expense) benefit on pension and other postretirement benefit plan adjustments									$ 14	$ (94)	$ 184

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities:
Net income (loss)	$ (105,693)	$ 205,794	$ 147,964
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization expense	281,460	297,874	264,232
Amortization of unit-based compensation	14,386	12,004	8,132
Amortization of debt related items	5,209	7,388	6,147
Loss from sale or disposition of assets	3,499	41,272	4,984
Gain from insurance recoveries	0	(78,756)	0
Asset and goodwill impairment losses	336,838	0	0
Deferred income tax (benefit) expense	(476)	2,043	6
Changes in current assets and current liabilities (Note 22)	(44,765)	78,262	(26,493)
Decrease (increase) in other long-term assets	22,020	(3,029)	943
(Decrease) increase in other long-term liabilities	(1,407)	(17,832)	2,414
Other, net	(2,314)	(813)	(1,530)
Net cash provided by operating activities	508,757	544,207	406,799
Cash Flows from Investing Activities:
Capital expenditures	(533,568)	(457,452)	(384,638)
Change in accounts payable related to capital expenditures	(12,731)	(7,683)	36,903
Acquisitions	0	(37,502)	(1,461,719)
Proceeds from Axeon term loan	0	0	110,000
Proceeds from insurance recoveries	0	78,419	977
Proceeds from sale or disposition of assets	228,152	270,440	2,036
Other, net	(1,100)	0	0
Net cash (used in) provided by investing activities	(319,247)	(153,778)	(1,696,441)
Cash Flows from Financing Activities:
Proceeds from long-term debt borrowings	659,300	1,254,153	1,465,767
Proceeds from short-term debt borrowings	307,500	618,500	1,051,000
Proceeds from note offering, net of issuance costs	491,580	0	543,333
Long-term debt repayments	(928,900)	(1,746,776)	(1,417,539)
Short-term debt repayments	(320,500)	(635,000)	(1,070,000)
Proceeds from issuance of Series D preferred units	0	590,000	0
Payment of issuance costs for Series D preferred units	0	(34,203)	0
Proceeds from issuance of other preferred units, net of issuance costs	0	0	538,560
Proceeds from issuance of common units, net of issuance costs	15,000	10,000	643,878
Contributions from general partner	0	204	13,737
Distributions to preferred unitholders	(121,693)	(90,670)	(38,833)
Distributions to common unitholders and general partner	(258,354)	(300,777)	(446,306)
Cash consideration for Merger (Note 4)	0	(67,795)	0
Proceeds from termination of interest rate swaps	0	8,048	0
Payment of tax withholding for unit-based compensation	(8,771)	(2,083)	(2,838)
(Decrease) increase in cash book overdrafts	(3,752)	2,935	1,736
Other, net	(9,060)	(6,403)	(6,223)
Net cash provided by (used in) financing activities	(177,650)	(399,867)	1,276,272
Effect of foreign exchange rate changes on cash	(524)	(1,210)	1,720
Net increase (decrease) in cash, cash equivalents and restricted cash	11,336	(10,648)	(11,650)
Cash, cash equivalents and restricted cash as of the beginning of the period	13,644	24,292	35,942
Cash, cash equivalents and restricted cash as of the end of the period	$ 24,980	$ 13,644	$ 24,292

CONSOLIDATED STATEMENTS OF PART

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]
Distribution Made to Limited Partner, Distributions Paid, Per Unit				$ 4.38
Partners' capital - beginning balance at Dec. 31, 2016	$ 1,611,617	$ (94,177)	$ 218,400	$ 1,455,642	$ 31,752
Temporary equity - beginning balance at Dec. 31, 2016	0
Partners' capital and temporary equity - beginning balance at Dec. 31, 2016	1,611,617
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	147,964	0	40,448	60,610	46,906
Net income (loss), excluding portion attributable to temporary equity	147,964
Net income, temporary equity							$ 0
Other comprehensive income (loss)	9,250	9,250	0	0	0
Cash distributions to partners			(40,448)	(391,737)	(54,569)	$ (446,306)
Issuance of units, including contribution from general partner	657,475	0	538,560	643,878	13,597
Unit-based compensation	2,656	0	0	2,516	140
Series D Preferred Unit accretion, common				0
Other	(679)	0	(357)	(322)	0
Other, temporary equity							0
Other, including temporary equity	(679)
Partners' capital - ending balance at Dec. 31, 2017	2,480,089	(84,927)	756,603	$ 1,770,587	37,826
Temporary equity - ending balance at Dec. 31, 2017	0
Partners' capital and temporary equity - ending balance at Dec. 31, 2017	2,480,089
Distribution Made to Limited Partner, Distributions Paid, Per Unit				$ 2.895
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						555,797
Unit-based compensation	7,925	0	0	7,925	0
Adjustments related to the Merger (refer to Note 4 for discussion)	(67,972)	0	0	(41,973)	(25,999)
Series D Preferred Unit accretion, common	(8,195)			(8,195)	0
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
Distribution Made to Limited Partner, Distributions Paid, Per Unit				$ 2.40
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	0	15,000	0
Unit-based compensation	20,766	0	0	20,766	0
Series D Preferred Unit accretion, common	(18,085)			(18,085)	0
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

ORGANIZATION AND OPERATIONS

ORGANIZATION AND OPERATIONS	12 Months Ended
	Dec. 31, 2019
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 Sale of St. Eustatius 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. Please refer to Note 5 for additional discussion. 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, we incurred losses of $5.4 million , which represent the aggregate amount of our deductibles under various insurance policies. We believe we have adequate insurance to offset additional costs in excess of the insurance deductibles. Other Events Sale of European Operations. 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 5 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 4 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 2017, we recorded a $5.0 million loss for property damage at the terminal, which represents the amount of our property deductible under our insurance policy, and we received insurance proceeds of $12.5 million , of which $3.8 million was for business interruption. In 2018, we received $87.5 million of insurance proceeds 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. Navigator Acquisition and Financing Transactions. On May 4, 2017 , we acquired Navigator Energy Services, LLC for approximately $1.5 billion (the Navigator Acquisition). In order to fund the purchase price, we issued 14,375,000 common units for net proceeds of $657.5 million , issued $550.0 million of 5.625% senior notes for net proceeds of $543.3 million and issued 15,400,000 of our 7.625% Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (Series B Preferred Units) for net proceeds of $371.8 million . Please refer to Notes 6 , 14 and 20 for further discussion. Axeon Term Loan. On February 22, 2017, we settled and terminated the $190.0 million term loan to Axeon Specialty Products, LLC (the Axeon Term Loan), pursuant to which we also provided credit support, such as guarantees, letters of credit and cash collateral, as applicable, of up to $125.0 million to Axeon Specialty Products, LLC (Axeon). We received $110.0 million in settlement of the Axeon Term Loan, and our obligation to provide ongoing credit support to Axeon ceased. 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 2,155 miles of crude oil pipelines, as well as approximately 5.2 million barrels of storage capacity, which comprise our Central West System. In addition, we own 2,600 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 approximately 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 approximately 61.3 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. Prior to the third quarter of 2017, our fuels marketing operations involved the purchase of crude oil, fuel oil, bunker fuel, fuel oil blending components and other refined products for resale. We ceased marketing crude oil in the second quarter of 2017 and exited our heavy fuels trading operations in the third quarter of 2017. These actions were in line with our goal of reducing our exposure to commodity margins, and instead focusing on our core, fee-based pipeline and storage segments. The remaining operations in our fuels marketing segment include our bunkering operations in the Gulf Coast, as well as certain of our blending operations associated with our Central East System.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2019
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 Trade receivables are carried at original invoice amount. We extend credit terms to certain customers after review of various credit indicators, including the customer’s credit rating. Outstanding customer receivable balances are regularly reviewed for possible non-payment indicators and allowances for doubtful accounts are recorded based upon management’s estimate of collectability at the time of its review. Inventories Inventories consist of petroleum products, materials and supplies. Inventories, except those associated with a qualifying fair value hedge, 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. Inventories associated with qualifying fair value hedges are valued at current market prices. Materials and supplies are valued at the lower of average cost or net realizable value. Restricted Cash As of December 31, 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 income (expense), 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 performed a qualitative assessment as of October 1, 2019 . Our qualitative assessment included, among other things, industry and market considerations, overall financial performance, other entity-specific events and events affecting individual reporting units. After assessing the totality of events or circumstances for each reporting unit, we determined that the carrying value did not exceed its fair value and that goodwill was not impaired. Our reporting units to which goodwill has been allocated consist of the following as of October 1, 2019: • crude oil pipelines; • refined product pipelines; and • terminals, excluding our Point Tupper facility and our refinery crude storage tanks. As discussed in Note 5 , we recognized a goodwill impairment charge in the first quarter of 2019 for the goodwill associated with the Statia Bunkering reporting unit, which consisted of our bunkering operations at the St. Eustatius terminal facility. 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. See Note 3 for a discussion of new accounting pronouncements. 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. We recognize an impairment of goodwill if the carrying value of goodwill exceeds its estimated fair value. 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 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. We performed a quantitative goodwill impairment test as of October 1, 2018 and determined that no impairment charges existed on that date. 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 5 , 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, 2019 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, 2019 and 2018 . 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 2018, 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. We have recorded liabilities of $0.2 million as of December 31, 2019 and 2018 , which are included in “Other long-term liabilities” in the consolidated balance sheets, for conditional asset retirement obligations related to the retirement of terminal assets with lease and right-of-way agreements. 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 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. Adoption of ASC Topic 606. On January 1, 2018, we adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (ASC Topic 606) using the modified retrospective method and applied ASC Topic 606 to all revenue contracts with customers. After identifying a contract with a customer, ASC Topic 606 requires us to (i) identify the performance obligations in the contract; (ii) determine the transaction price; (iii) allocate the transaction price to the performance obligations; and (iv) recognize revenue when or as we satisfy a performance obligation. 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. Similarly, 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). 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. 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 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, it becomes 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 4 for further discussion of the merger and Note 20 for the calculation of net income applicable to the general partner prior to 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 24 for additional information on our performance units, Note 19 for additional information on our Series D Preferred Units and Note 21 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. Under the terms of our forward-starting interest rate swap agreements, we pay a fixed rate and receive a variable rate. We entered 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 the effective portion of mark-to-market adjustments as a component of accumulated other comprehensive income (loss) (AOCI), and any hedge ineffectiveness is recognized immediately in “Interest expense, net.” 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 18 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 24 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 income (expense), 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. As further discussed in Note 5

NEW ACCOUNTING PRONOUNCEMENTS

NEW ACCOUNTING PRONOUNCEMENTS	12 Months Ended
	Dec. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS Simplifying the Accounting for Income Taxes In December 2019, the Financial Accounting Standards Board (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 are currently evaluating the impact of this amended guidance on our financial position, results of operations or disclosures and whether we will adopt these provisions early. Securities and Exchange Commission Disclosure Update and Simplification In August 2018, the Securities and Exchange Commission (SEC) issued final rules regarding disclosure requirements that were redundant, duplicative, overlapping or superseded by other SEC requirements or GAAP. The final rules primarily eliminated or reduced certain disclosure requirements, although they also required some additional disclosures. The rules became effective on November 5, 2018, with an exception for the new disclosure requirement to present changes in partners’ equity in interim periods, which permits entities to begin disclosing this information in the quarter that begins after the effective date of the final rules. We elected to utilize this exception, and began presenting statements of partners’ equity on an interim basis beginning with the quarter ending March 31, 2019. These final rules did not have an impact on our financial position or results of operations. 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. Under the new guidance, implementation costs for a CCA should be evaluated for capitalization using the same approach as implementation costs associated with internal-use software and expensed over the term of the hosting arrangement. 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 it did not have a material impact on our financial position or results of operations, and we do not expect it to have a material impact on our 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 beginning after December 15, 2020, with early adoption permitted, using a retrospective approach. We are currently evaluating whether we will adopt these provisions early, but we do not expect the guidance to have a material impact on our financial position, results of operations or disclosures. Unit-Based Payments to Nonemployees In June 2018, the FASB issued amended guidance which aligns the measurement and classification guidance for unit-based payments to nonemployees with the guidance for unit-based payments to employees, with certain exceptions. Under the amended guidance, unit-based payment awards to nonemployees will be measured at their grant date fair value. The guidance is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. The amended guidance should be applied by means of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. We adopted these provisions on January 1, 2019, and the guidance did not have a material impact on our financial position, results of operations or disclosures. Goodwill In January 2017, the FASB issued amended guidance that simplifies the accounting for goodwill impairment. Under the amended guidance, goodwill impairment is measured as the excess of the reporting unit’s carrying value over its fair value, not to exceed the carrying amount of goodwill for that reporting unit. The changes are effective for annual and interim periods beginning after December 15, 2019, and amendments should be applied prospectively. Early adoption is permitted for any impairment tests performed after January 1, 2017. We adopted the amended guidance during the first quarter of 2019 and applied the guidance to the goodwill impairment discussed in Note 5 . 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 it did not have a material impact on our financial position or results of operations, and we do not expect it to have a material impact on our disclosures. Leases In February 2016, the FASB issued amended guidance that requires lessees to recognize the assets and liabilities that arise from most leases on the balance sheet. For lessors, this amended guidance modifies the classification criteria and the accounting for sales-type and direct financing leases. The changes are effective for annual and interim periods beginning after December 15, 2018, and amendments should be applied using one of two modified retrospective transition methods. We adopted these provisions on January 1, 2019 through a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The transition adjustment related to the adoption was immaterial , and the adoption of this guidance did not materially impact the results of our operations. Please refer to Note 17 for further discussion.

MERGER AND RELATED PARTY AGREEM

MERGER AND RELATED PARTY AGREEMENTS	12 Months Ended
	Dec. 31, 2019
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 . On July 19, 2006, we entered into a non-compete agreement with Holdings, Riverwalk Logistics, L.P. and NuStar GP, LLC (the Non-Compete Agreement). The Non-Compete Agreement became effective on December 22, 2006. 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.

DISCONTINUED OPERATIONS AND IMP

DISCONTINUED OPERATIONS AND IMPAIRMENTS	12 Months Ended
	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	DISCONTINUED OPERATIONS AND IMPAIRMENTS 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 related to the sale in “(Loss) income from discontinued operations, net of tax” on the consolidated statement of income for the year ended December 31, 2018. 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 3 , 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. 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 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. Discontinued Operations 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 2017 (Thousands of Dollars) Revenues $ 248,981 $ 441,495 $ 369,247 Costs and expenses: Cost of revenues 220,595 407,256 318,532 Impairment losses 336,838 — — General and administrative expenses (excluding depreciation and amortization expense) 1,231 6,133 4,684 Other depreciation and amortization expense — 271 263 Total costs and expenses 558,664 413,660 323,479 Operating (loss) income (309,683 ) 27,835 45,768 Interest income (expense), net 32 (1,839 ) (1,309 ) Other (expense) income, net (2,775 ) 34,674 (5,226 ) (Loss) income from discontinued operations before income tax expense (312,426 ) 60,670 39,233 Income tax expense 101 1,251 2,164 (Loss) income from discontinued operations, net of tax $ (312,527 ) $ 59,419 $ 37,069 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 2017 (Thousands of Dollars) Capital expenditures $ (27,954 ) $ (114,811 ) $ (153,785 ) Significant noncash operating activities and other adjustments: Depreciation and amortization expense $ 8,536 $ 41,982 $ 36,040 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 ) $ — Assets and Liabilities Held for Sale The following is a reconciliation of the carrying amounts of the major classes of assets and liabilities included in “Assets held for sale” and “Liabilities held for sale” on the consolidated balance sheet: December 31, 2018 (Thousands of Dollars) Total current assets $ 54,404 Property, plant and equipment, net 513,820 Goodwill 31,123 Assets held for sale $ 599,347 Current liabilities $ 69,834

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Council Bluffs Acquisition. On April 16, 2018, we acquired CHS Inc.’s Council Bluffs pipeline system, comprised of a 227-mile pipeline and 18 storage tanks , for approximately $37.5 million . The assets acquired and the results of operations are included in our pipeline segment from the date of acquisition. We accounted for this acquisition as an asset purchase. Navigator Acquisition. On May 4, 2017 , we acquired Navigator Energy Services, LLC (Navigator) for approximately $1.5 billion (the Navigator Acquisition). We acquired crude oil transportation, pipeline connection and storage assets located in the Midland Basin in West Texas that, together with the assets we have constructed through various expansion projects since the date of the Navigator Acquisition, we collectively refer to as our Permian Crude System. The assets acquired are included in our pipeline segment. The consolidated statements of (loss) income include the results of operations for Navigator commencing on May 4, 2017. We accounted for the Navigator Acquisition using the acquisition method. The following table reflects the final purchase price allocation: Purchase Price Allocation (Thousands of Dollars) Accounts receivable $ 4,747 Other current assets 2,359 Property, plant and equipment, net 376,690 Intangible assets (a) 700,000 Goodwill (b) 398,024 Other long-term assets, net 2,199 Current liabilities (22,300 ) Purchase price allocation, net of cash acquired $ 1,461,719 (a) Intangible assets, which consist of customer contracts and relationships, are amortized on a straight-line basis over a period of 20 years . (b) The goodwill acquired represents the expected benefit from entering new geographic areas and the anticipated opportunities to generate future cash flows from the assets acquired and potential future projects. The unaudited pro forma information for the year ended December 31, 2017 below presents the combined historical financial information for Navigator and the Partnership for those periods. This information assumes: • we completed the Navigator Acquisition on January 1, 2017; • we issued approximately 14.4 million common units; • we received a contribution from our general partner of $13.6 million to maintain the 2% general partner economic interest it owned at that time; • we issued 15.4 million Series B Preferred Units; • we issued $550.0 million of 5.625% senior notes; • additional depreciation and amortization that would have been incurred assuming the fair value adjustments to property, plant and equipment and intangible assets reflected in the purchase price allocation above; and • we satisfied Navigator’s outstanding obligations under its revolving credit agreement. Year Ended December 31, 2017 (Thousands of Dollars, Except Per Unit Data) Revenues $ 1,828,418 Net income $ 127,433 Basic and diluted net income per common unit $ 0.31 The pro forma information for the year ended December 31, 2017 includes transaction costs of $14.1 million , which were directly attributable to the Navigator Acquisition. The pro forma information is unaudited and is not necessarily indicative of the results of operations that would have resulted had the Navigator Acquisition occurred on January 1, 2017 or that may result in the future.

REVENUE FROM CONTRACTS WITH CUS

REVENUE FROM CONTRACTS WITH CUSTOMERS	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS Transition On January 1, 2018, we adopted ASC Topic 606 using the modified retrospective method and applied ASC Topic 606 to all revenue contracts with customers. Results for reporting periods beginning January 1, 2018 are presented under ASC Topic 606. In accordance with the modified retrospective approach, prior period amounts were not adjusted and are reported under ASC Topic 605, “Revenue Recognition.” The adoption of ASC Topic 606 affected our consolidated statements of (loss) income as follows: As Reported Without Adoption of ASC Topic 606 Effect of Change Higher/(Lower) (Thousands of Dollars, Except Per Unit Data) For the year ended December 31, 2018: Revenues $ 1,520,262 $ 1,526,447 $ (6,185 ) Operating income $ 335,728 $ 341,913 $ (6,185 ) Income from continuing operations $ 146,375 $ 152,560 $ (6,185 ) Basic net loss per common unit from continuing operations $ (3.34 ) $ (3.27 ) $ (0.07 ) Contract Assets and Contract Liabilities The following table provides information about contract assets and contract liabilities from contracts with customers: 2019 2018 Contract Assets Contract Liabilities Contract Assets Contract Liabilities (Thousands of Dollars) (Thousands of Dollars) Balances as of January 1: Current portion $ 2,066 $ (21,579 ) $ 1,956 $ (13,801 ) Noncurrent portion 539 (38,945 ) 171 (46,361 ) Held for sale — (25,357 ) — (302 ) Total 2,605 (85,881 ) 2,127 (60,464 ) Activity: Additions 4,890 (52,957 ) 3,281 (83,243 ) Transfer to accounts receivable (4,352 ) — (2,803 ) — Transfer to revenues, including amounts reported in discontinued operations — 77,466 — 57,826 Total 538 24,509 478 (25,417 ) Balances as of December 31: Current portion 2,140 (21,083 ) 2,066 (21,579 ) Noncurrent portion 1,003 (40,289 ) 539 (38,945 ) Held for sale — — — (25,357 ) Total $ 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, 2019 (in thousands of dollars): 2020 $ 529,830 2021 376,500 2022 310,632 2023 236,853 2024 175,358 Thereafter 255,808 Total $ 1,884,981 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, 2019 2018 2017 (Thousands of Dollars) Pipeline segment: Crude oil pipelines $ 316,417 $ 248,261 $ 187,874 Refined products and ammonia pipelines (excluding lessor revenues) 376,588 362,750 328,414 Total pipeline segment revenues from contracts with customers 693,005 611,011 516,288 Lessor revenues 8,825 54 — Total pipeline segment revenues 701,830 611,065 516,288 Storage segment: Throughput terminals 114,243 83,157 85,927 Storage terminals (excluding lessor revenues) 298,984 320,582 317,963 Total storage segment revenues from contracts with customers 413,227 403,739 403,890 Lessor revenues 40,774 39,849 39,126 Total storage segment revenues 454,001 443,588 443,016 Fuels marketing segment: Revenues from contracts with customers 342,215 465,651 489,807 Consolidation and intersegment eliminations (25 ) (42 ) (4,339 ) Total revenues $ 1,498,021 $ 1,520,262 $ 1,444,772

ALLOWANCE FOR DOUBTFUL ACCOUNTS

ALLOWANCE FOR DOUBTFUL ACCOUNTS	12 Months Ended
	Dec. 31, 2019
Accounts Receivable Additional Disclosures [Abstract]
ALLOWANCE FOR DOUBTFUL ACCOUNTS	ALLOWANCE FOR DOUBTFUL ACCOUNTS The changes in the allowance for doubtful accounts consisted of the following: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Balance as of beginning of year $ 9,412 $ 9,380 $ 7,700 Increase in allowance, net 2,322 233 1,705 Accounts charged against the allowance (11,662 ) (201 ) (25 ) Balance as of end of year $ 72 $ 9,412 $ 9,380

INVENTORIES

INVENTORIES	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Inventories consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Petroleum products $ 8,646 $ 4,853 Materials and supplies 3,747 3,581 Total $ 12,393 $ 8,434 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

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consisted of the following: Estimated Useful Lives December 31, 2019 2018 (Years) (Thousands of Dollars) Land - $ 144,409 $ 138,487 Land and leasehold improvements 5 - 40 223,220 181,578 Buildings 15 - 40 166,878 146,517 Pipelines, storage and terminals 15 - 40 5,038,468 4,702,421 Rights-of-way 20 - 40 350,026 301,738 Construction in progress - 264,143 157,064 Total 6,187,144 5,627,805 Less accumulated depreciation and amortization (2,068,165 ) (1,853,003 ) Property, plant and equipment, net $ 4,118,979 $ 3,774,802 Capitalized interest costs added to property, plant and equipment, including amounts related to discontinued operations, totaled $8.9 million , $7.8 million and $5.5 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Depreciation and amortization expense for property, plant and equipment totaled $226.0 million , $243.5 million and $222.5 million for the years ended December 31, 2019 , 2018 and 2017 , 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

INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2019
Intangible Assets, Net (Excluding Goodwill) [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS Intangible assets consisted of the following: Weighted-Average Amortization Period December 31, 2019 December 31, 2018 Cost Accumulated Amortization Cost Accumulated Amortization (Years) (Thousands of Dollars) Customer contracts and relationships 18 $ 863,900 $ (183,832 ) $ 863,950 $ (132,509 ) Other 47 2,359 (795 ) 2,359 (744 ) Total $ 866,259 $ (184,627 ) $ 866,309 $ (133,253 ) 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 , $51.4 million and $39.6 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. The estimated aggregate amortization expense is approximately $51.0 million for each of the years 2020 through 2022 , and approximately $45.0 million for 2023 and 2024 .

GOODWILL

GOODWILL	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL Changes in the carrying amount of goodwill by segment were as follows: Pipeline Storage Total (Thousands of Dollars) Balances as of January 1, 2018 $ 707,045 $ 301,622 $ 1,008,667 Activity for the year ended December 31, 2018: Navigator Acquisition purchase price allocation adjustments (Note 6) (2,814 ) — (2,814 ) Balances as of December 31, 2018 and 2019 $ 704,231 $ 301,622 $ 1,005,853 As discussed in Note 5 , 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 connection with the European Disposition in 2018, we allocated goodwill of $57.7 million to the European Operations. 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 5 for additional information. As a result of the St. Eustatius Disposition, there are no accumulated impairment losses associated with continuing operations as of December 31, 2019.

ACCRUED LIABILITIES

ACCRUED LIABILITIES	12 Months Ended
	Dec. 31, 2019
Accrued Liabilities, Current [Abstract]
ACCRUED LIABILITIES	ACCRUED LIABILITIES Accrued liabilities consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Employee wages and benefit costs $ 36,704 $ 29,518 Revenue contract liabilities 21,083 21,579 Interest rate swaps 19,169 — Operating lease liabilities 10,416 — Other 16,913 23,321 Accrued liabilities $ 104,285 $ 74,418

DEBT

DEBT	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
DEBT	DEBT Short-term debt consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Short-term line of credit $ 5,500 $ 18,500 Current portion of finance leases (refer to Note 17) 4,546 — Short-term debt and current portion of finance leases $ 10,046 $ 18,500 NuStar Logistics is party to a short-term line of credit agreement with an uncommitted borrowing capacity of up to $35.0 million , which allows us to better manage fluctuations in our daily cash requirements and minimize our excess cash balances. The interest rates and maturities vary and are determined at the time of borrowing. Obligations under this short-term line of credit agreement are guaranteed by NuStar Energy. As of December 31, 2019 and 2018 , the weighted-average interest rates related to outstanding borrowings under our short-term line of credit were 3.6% and 4.4% , respectively. Long-term debt consisted of the following: December 31, Maturity 2019 2018 (Thousands of Dollars) Revolving Credit Agreement 2021 $ 475,000 $ 745,000 4.80% senior notes 2020 450,000 450,000 6.75% senior notes 2021 300,000 300,000 4.75% senior notes 2022 250,000 250,000 6.00% senior notes 2026 500,000 — 5.625% senior notes 2027 550,000 550,000 Subordinated Notes 2043 402,500 402,500 GoZone Bonds 2038 thru 2041 365,440 365,440 Receivables Financing Agreement 2021 62,200 61,800 Net fair value adjustments, unamortized discounts and unamortized debt issuance costs N/A (23,301 ) (12,744 ) Total long-term debt (excluding finance leases) 3,331,839 3,111,996 Finance leases (refer to Note 17) 55,446 — Less current portion 452,367 — Long-term debt, less current portion $ 2,934,918 $ 3,111,996 The long-term debt repayments (excluding finance leases) are due as follows (in thousands of dollars): 2020 $ 450,000 2021 837,200 2022 250,000 2023 — 2024 — Thereafter 1,817,940 Total repayments 3,355,140 Net fair value adjustments, unamortized discounts and unamortized debt issuance costs (23,301 ) Total long-term debt (excluding finance leases) $ 3,331,839 We expect to refinance senior note maturities in 2020 and 2021 by utilizing the capital markets, pursuing other sources of debt financing or with funds available under our revolving credit agreement. Interest payments totaled $183.8 million , $190.9 million and $163.6 million for the years ended December 31, 2019 , 2018 and 2017 , respectively, related to debt obligations. We amortized an aggregate of $6.5 million , $7.1 million and $5.0 million of debt issuance costs and debt discount combined for the years ended December 31, 2019 , 2018 and 2017 , respectively. Revolving Credit Agreement On September 12, 2019, NuStar Logistics amended its revolving credit agreement (the Revolving Credit Agreement) primarily to extend the maturity date to October 29, 2021 and reduce the total amount available for borrowing from $1.4 billion to $1.2 billion . For the rolling period ending December 31, 2019, 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 maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio requirements may limit the amount we can borrow under the Revolving Credit Agreement to an amount less than the total amount available for borrowing. 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, 2019 , we believe that we are in compliance with the covenants in the Revolving Credit Agreement. As of December 31, 2019 , we had $721.0 million available for borrowing. Obligations under the Revolving Credit Agreement are guaranteed by NuStar Energy and NuPOP. Letters of credit issued under the Revolving Credit Agreement totaled $4.0 million as of December 31, 2019 . Letters of credit are limited to $400.0 million and also may restrict the amount we can borrow under the Revolving Credit Agreement. The Revolving Credit Agreement bears interest, at our option, based on an alternative base rate, a LIBOR-based rate or a EURIBOR-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. As of December 31, 2019 , our weighted-average interest rate was 3.9% , and we had $475.0 million outstanding. During the year ended December 31, 2019 , the weighted-average interest rate related to borrowings under the Revolving Credit Agreement was 4.4% . Notes NuStar Logistics Senior Notes. 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. On April 28, 2017 , NuStar Logistics issued $550.0 million of 5.625% senior notes due April 28, 2027 . We used the net proceeds of $543.3 million from the offering to fund a portion of the purchase price for the Navigator Acquisition and to pay related fees and expenses. The interest on the 5.625% senior notes is payable semi-annually in arrears on April 28 and October 28 of each year, beginning on October 28, 2017. Interest is payable semi-annually in arrears for the $450.0 million of 4.80% senior notes, $300.0 million of 6.75% senior notes, $250.0 million of 4.75% senior notes, $500.0 million of 6.0% senior notes and $550.0 million of 5.625% senior notes (collectively, the NuStar Logistics Senior Notes). We repaid the $350.0 million of 7.65% senior notes on April 15, 2018 with borrowings under our Revolving Credit Agreement. 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 additional 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 NuStar Logistics’ ability to incur indebtedness secured by certain liens and to 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 6.0% senior notes or the 5.625% senior notes, each holder of the 6.75% senior notes, the 6.0% senior notes or the 5.625% 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. 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, 2019 , the interest rate was 8.7% . 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). The interest rates on these bonds are based on a weekly tax-exempt bond market interest rate, and interest is paid monthly. 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 expansions. We include the amount remaining in the trust in “Other long-term assets, net,” and we include the amount of bonds issued in “Long-term debt” in our consolidated balance sheets. We did not receive any proceeds from the trustee for the years ended December 31, 2019 and 2018 . NuStar Logistics is solely obligated to service the principal and interest payments associated with the GoZone Bonds. Letters of credit were issued by various individual banks on our behalf to guarantee the payment of interest and principal on the bonds. All letters of credit rank equally with existing senior unsecured indebtedness of NuStar Logistics and generally contain the same restrictive covenants, maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio requirements as the Revolving Credit Agreement. Obligations under the letters of credit issued are guaranteed by NuStar Energy and NuPOP. The letters of credit issued by individual banks do not restrict the amount we can borrow under the Revolving Credit Agreement. At the option of NuStar Logistics, during any period when the bonds bear interest at a daily or weekly rate, the GoZone Bonds may be redeemed in whole or in part on any interest payment date for 100% of the outstanding principal amount plus accrued interest to the redemption date. On January 27, 2020, NuStar Logistics provided the trustee with notice to call the $43.3 million principal amount of the GoZone Bonds remaining in trust for redemption on March 4, 2020. The following table summarizes the GoZone Bonds outstanding as of December 31, 2019 : Date Issued Maturity Date Amount Outstanding Amount of Letter of Credit Amount Received from Trustee Amount Remaining in Trust (a) Interest Rate (b) (Thousands of Dollars) June 26, 2008 June 1, 2038 $ 55,440 $ 56,169 $ 55,440 $ — 1.6 % July 15, 2010 July 1, 2040 100,000 101,315 100,000 — 1.5 % October 7, 2010 October 1, 2040 50,000 50,658 43,741 6,652 1.5 % December 29, 2010 December 1, 2040 85,000 86,118 49,782 36,580 1.5 % August 9, 2011 August 1, 2041 75,000 75,986 75,000 — 1.6 % Total $ 365,440 $ 370,246 $ 323,963 $ 43,232 (a) Amount remaining in trust includes accrued interest. (b) For the year ended December 31, 2019 , our weighted-average interest rate on borrowings was 1.5% . 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 $125.0 million 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). 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 limited to $125.0 million and 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. On April 29, 2019, we amended the Receivables Financing Agreement to extend the scheduled termination date from September 20, 2020 to September 20, 2021, with the option to renew for additional 364-day periods thereafter, and to amend certain provisions with respect to receivables related to certain customers. 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, 2019 and 2018 , accounts receivable totaling $112.8 million and $95.5 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, 2019 was 3.2% .

HEALTH, SAFETY AND ENVIRONMENTA

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS	12 Months Ended
	Dec. 31, 2019
Environmental Remediation Obligations [Abstract]
HEALTH, SAFETY AND ENVIRONMENTAL MATTERS	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 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, 2019 2018 (Thousands of Dollars) Balance as of the beginning of year $ 7,753 $ 5,095 Additions to accrual 3,700 5,708 Payments (3,515 ) (3,050 ) Balance as of the end of year $ 7,938 $ 7,753 Accruals for environmental matters are included in the consolidated balance sheets as follows: December 31, 2019 2018 (Thousands of Dollars) Accrued liabilities $ 4,837 $ 4,349 Other long-term liabilities 3,101 3,404 Accruals for environmental matters $ 7,938 $ 7,753

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES 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 $3.7 million and $2.8 million for contingent losses as of December 31, 2019 and 2018 , 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. Commitments Future minimum rental payments applicable to all noncancellable purchase obligations as of December 31, 2019 are as follows: Payments Due by Period 2020 2021 2022 2023 2024 There- after Total (Thousands of Dollars) Purchase obligations $ 8,935 $ 7,643 $ 6,202 $ 1,485 $ 812 $ 5,157 $ 30,234 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.

LEASE ASSETS AND LIABILITIES

LEASE ASSETS AND LIABILITIES	12 Months Ended
	Dec. 31, 2019
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. 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, 2019, land and dock leases have remaining terms generally of up to 6 years and include options to extend, some up to 20 years , which we are reasonably certain to exercise. 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 1 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: Balance Sheet Location December 31, 2019 (Thousands of Dollars) Right-of-Use Assets: Operating Other long-term assets, net $ 81,219 Finance Property, plant and equipment, net of accumulated amortization of $3,748 $ 74,953 Lease Liabilities: Operating: Current Accrued liabilities $ 10,416 Noncurrent Other long-term liabilities 70,083 Total operating lease liabilities $ 80,499 Finance: Current Short-term debt and current portion of finance leases $ 4,546 Noncurrent Long-term debt, less current portion 55,446 Total finance lease liabilities $ 59,992 As of December 31, 2019 , maturities of our operating and finance lease liabilities were as follows: Operating Leases Finance Leases (Thousands of Dollars) 2020 $ 12,647 $ 6,702 2021 9,419 5,252 2022 8,717 4,582 2023 7,605 4,480 2024 6,739 4,067 Thereafter 60,354 59,681 Total lease payments $ 105,481 $ 84,764 Less: Interest 24,982 24,772 Present value of lease liabilities $ 80,499 $ 59,992 Costs incurred for leases, including costs associated with discontinued operations, were as follows: Year Ended December 31, 2019 (Thousands of Dollars) Operating lease cost $ 29,167 Finance lease cost: Amortization of right-of-use assets 3,748 Interest expense on lease liability 2,212 Short-term lease cost 19,140 Variable lease cost 6,990 Total lease cost $ 61,257 Rental expense for operating leases (pursuant to ASC Topic 840) totaled $42.9 million and $36.2 million for the years ended December 31, 2018 and 2017 , respectively, 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: Operating Leases Finance Leases (Thousands of Dollars, Except Term and Rate Data) For the year ended December 31, 2019: Cash outflows from operating activities $ 27,567 $ 2,027 Cash outflows from financing activities $ — $ 3,700 Right-of-use assets obtained in exchange for lease liabilities $ 2,153 $ 4,430 As of December 31, 2019: Weighted-average remaining lease term (in years) 15 20 Weighted-average discount rate 3.6 % 3.7 %
Lessee, Finance 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. 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, 2019, land and dock leases have remaining terms generally of up to 6 years and include options to extend, some up to 20 years , which we are reasonably certain to exercise. 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 1 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: Balance Sheet Location December 31, 2019 (Thousands of Dollars) Right-of-Use Assets: Operating Other long-term assets, net $ 81,219 Finance Property, plant and equipment, net of accumulated amortization of $3,748 $ 74,953 Lease Liabilities: Operating: Current Accrued liabilities $ 10,416 Noncurrent Other long-term liabilities 70,083 Total operating lease liabilities $ 80,499 Finance: Current Short-term debt and current portion of finance leases $ 4,546 Noncurrent Long-term debt, less current portion 55,446 Total finance lease liabilities $ 59,992 As of December 31, 2019 , maturities of our operating and finance lease liabilities were as follows: Operating Leases Finance Leases (Thousands of Dollars) 2020 $ 12,647 $ 6,702 2021 9,419 5,252 2022 8,717 4,582 2023 7,605 4,480 2024 6,739 4,067 Thereafter 60,354 59,681 Total lease payments $ 105,481 $ 84,764 Less: Interest 24,982 24,772 Present value of lease liabilities $ 80,499 $ 59,992 Costs incurred for leases, including costs associated with discontinued operations, were as follows: Year Ended December 31, 2019 (Thousands of Dollars) Operating lease cost $ 29,167 Finance lease cost: Amortization of right-of-use assets 3,748 Interest expense on lease liability 2,212 Short-term lease cost 19,140 Variable lease cost 6,990 Total lease cost $ 61,257 Rental expense for operating leases (pursuant to ASC Topic 840) totaled $42.9 million and $36.2 million for the years ended December 31, 2018 and 2017 , respectively, 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: Operating Leases Finance Leases (Thousands of Dollars, Except Term and Rate Data) For the year ended December 31, 2019: Cash outflows from operating activities $ 27,567 $ 2,027 Cash outflows from financing activities $ — $ 3,700 Right-of-use assets obtained in exchange for lease liabilities $ 2,153 $ 4,430 As of December 31, 2019: Weighted-average remaining lease term (in years) 15 20 Weighted-average discount rate 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 $40.8 million for the year ended December 31, 2019 , which are included in “Service revenues” in the consolidated statements of (loss) income . As of December 31, 2019 , we expect to receive minimum lease payments totaling $273.7 million , based upon the consumer price index as of the adoption date. We will recognize these payments ratably over the remaining initial lease term. As of December 31, 2019 , the cost and accumulated depreciation of lease storage assets, which are included in our “Pipeline, storage and terminals” asset class within property, plant and equipment and have an estimated useful life of 30 years , total $238.2 million and $121.5 million , respectively.

DERIVATIVES AND FAIR VALUE MEAS

DERIVATIVES AND FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
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. 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 are a party to certain interest rate swap agreements that terminate in September 2020 to manage our exposure to changes in interest rates, which consist of forward-starting interest rate swap agreements related to a forecasted debt issuance in 2020. 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 pay a fixed rate and receive a rate based on the three-month USD LIBOR . These swaps qualify as cash flow hedges, and we designate them as such. We record the effective portion of mark-to-market adjustments as a component of AOCI, and the amount in AOCI will be recognized in “Interest expense, net” as the forecasted interest payments occur or if the interest payments are probable not to occur. As of December 31, 2019 and 2018 , the aggregate notional amount of forward-starting interest rate swaps totaled $250.0 million . 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 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 2019 2018 (Thousands of Dollars) Fixed-to-floating Current portion of long-term debt $ 2,755 $ — Fixed-to-floating Long-term debt, less current portion $ 2,568 $ 10,475 Forward-starting Accumulated other comprehensive income (loss) $ 3,045 $ (770 ) The fair values of our interest rate swap agreements included in our consolidated balance sheets were as follows: Balance Sheet Location December 31, 2019 2018 (Thousands of Dollars) Other long-term assets, net $ — $ 627 Accrued liabilities $ (19,169 ) $ — Other long-term liabilities $ — $ (751 ) Our forward-starting interest rate swaps had the following impact on earnings: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) (Loss) gain recognized in other comprehensive income (loss) on derivative $ (19,045 ) $ 17,912 $ (8,670 ) Loss reclassified from AOCI into interest expense, net $ (3,814 ) $ (5,499 ) $ (6,624 ) As of December 31, 2019 , we expect to reclassify a loss of $2.4 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. Because we estimate the fair value of our forward-starting interest rate swaps using discounted cash flows, which use observable inputs such as time to maturity and market interest rates, we include interest rate swaps in Level 2 of the fair value hierarchy. 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, 2019 December 31, 2018 (Thousands of Dollars) Fair value $ 3,442,001 $ 3,056,704 Carrying amount $ 3,331,839 $ 3,111,996 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.

SERIES D CUMULATIVE CONVERTIBLE

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS	12 Months Ended
	Dec. 31, 2019
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 rate on the Series D Preferred Units is: (i) 9.75% per annum ( $57.6 million per annum) for the first two years; (ii) 10.75% per annum ( $63.4 million per annum) for years three through five; and (iii) the greater of 13.75% per annum ($81.1 million per annum) 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 2020, our board of directors declared a distribution of $0.619 per Series D Preferred Unit to be paid on March 16, 2020. Series D Preferred Units Conversion and Redemption Features At any time 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

PARTNERS' EQUITY	12 Months Ended
	Dec. 31, 2019
Partners' Capital Notes [Abstract]
PARTNERS' EQUITY	PARTNERS’ EQUITY Please refer to Note 4 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 19 . In 2017, the partnership agreement was amended and restated in connection with the issuances of our Series B Preferred Units and Series C Preferred Units described below, and in connection with the Navigator Acquisition to waive certain distributions to our general partner. 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, 2019 : Units Original Issuance Date Number of Units Issued and Outstanding Price per Unit Net Proceeds (in millions) 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 $ 218.4 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 $ 371.8 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 $ 166.7 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 2020, our board of directors declared quarterly distributions with respect to the Series A, B and C Preferred Units to be paid on March 16, 2020. 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 4 , 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. In the second quarter of 2017, we issued 14,375,000 common units at a price of $46.35 per unit. We used the net proceeds from this offering of $657.5 million , including a contribution of $13.6 million from our general partner to maintain the 2% general partner economic interest it owned at that time, to fund a portion of the purchase price for the Navigator Acquisition. The following table shows the balance of and changes in the number of our common units outstanding: Year Ended December 31, 2019 2018 2017 Balance as of the beginning of year 107,225,156 93,176,683 78,616,228 Issuance of units 527,426 413,736 14,375,000 Unit-based compensation (refer to Note 24 for discussion) 775,224 225,144 185,455 Merger (refer to Note 4 for discussion) — 13,409,593 — Balance as of the end of year 108,527,806 107,225,156 93,176,683 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. Prior to the Merger, our Available Cash was distributed based on the percentages shown below: Percentage of Distribution Quarterly Distribution Amount Per Common Unit Common Unitholders General Partner Including Incentive Distributions Up to $0.60 98% 2% Above $0.60 up to $0.66 90% 10% Above $0.66 75% 25% 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. The following table reflects the allocation of total cash distributions to the general partner and common limited partners applicable to the period in which the distributions were earned: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars, Except Per Unit Data) General partner interest $ — $ 1,141 $ 9,252 General partner incentive distribution — — 45,669 Total general partner distribution — 1,141 54,921 Common limited partners’ distribution 259,136 248,705 407,681 Total cash distributions $ 259,136 $ 249,846 $ 462,602 Cash distributions per unit applicable to common limited partners $ 2.40 $ 2.40 $ 4.38 The following table summarizes information about quarterly cash distributions declared for our common limited partners applicable to the year ended December 31, 2019 : Quarter Ended Cash Distributions Per Unit Total Cash Distributions Record Date Payment Date (Thousands of Dollars) December 31, 2019 $ 0.60 $ 65,128 February 10, 2020 February 14, 2020 September 30, 2019 $ 0.60 $ 64,660 November 8, 2019 November 14, 2019 June 30, 2019 $ 0.60 $ 64,658 August 7, 2019 August 13, 2019 March 31, 2019 $ 0.60 $ 64,690 May 8, 2019 May 14, 2019 Net Income Applicable to the General Partner. For the year ended December 31, 2018, net income applicable to the general partner totaled $2.5 million and related to the general partner interest allocation prior to the Merger. The following table details the calculation of net income applicable to the general partner for 2017: Year Ended December 31, 2017 (Thousands of Dollars) Net income attributable to NuStar Energy L.P. $ 147,964 Less preferred limited partner interest 40,448 Less general partner incentive distribution 45,669 Net income after general partner incentive distribution and preferred limited partner interest 61,847 General partner interest allocation 2 % General partner interest allocation of net income 1,237 General partner incentive distribution 45,669 Net income applicable to general partner $ 46,906 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, 2017 $ (69,069 ) $ (22,258 ) $ (2,850 ) $ (94,177 ) Other comprehensive income (loss) before reclassification adjustments 17,466 (8,670 ) (4,641 ) 4,155 Net gain on pension costs reclassified into operating expense — — (1,143 ) (1,143 ) Net gain on pension costs reclassified into general and administrative expense — — (386 ) (386 ) Net loss on cash flow hedges reclassified into interest expense, net — 6,624 — 6,624 Other comprehensive income (loss) 17,466 (2,046 ) (6,170 ) 9,250 Balance as of December 31, 2017 (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 )

NET (LOSS) INCOME PER COMMON UN

NET (LOSS) INCOME PER COMMON UNIT	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
NET (LOSS) INCOME PER UNIT	NET (LOSS) INCOME PER COMMON UNIT As discussed in Note 19 , the Series D Preferred Units are convertible into common units at the option of the holder at any time on or after June 29, 2028. 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, 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. Refer to Note 24 for additional discussion. The following table details the calculation of net (loss) income per common unit: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars, Except Unit and Per Unit Data) Net (loss) income $ (105,693 ) $ 205,794 $ 147,964 Distributions to preferred limited partners (121,693 ) (92,540 ) (40,448 ) Distributions to general partner (including incentive distribution rights) — (1,141 ) (54,921 ) Distributions to common limited partners (259,136 ) (248,705 ) (407,681 ) Distribution equivalent rights to restricted units (2,659 ) (2,045 ) (2,965 ) Distributions in excess of (loss) income $ (489,181 ) $ (138,637 ) $ (358,051 ) Distributions to common limited partners $ 259,136 $ 248,705 $ 407,681 Allocation of distributions in excess of (loss) income (489,181 ) (138,659 ) (350,890 ) Series D Preferred Unit accretion (refer to Note 19) (18,085 ) (8,195 ) — Loss to common unitholders attributable to the Merger (refer to Note 4) — (377,079 ) — Net (loss) income attributable to common units $ (248,130 ) $ (275,228 ) $ 56,791 Basic weighted-average common units outstanding 107,789,030 99,490,495 88,825,964 Diluted common units outstanding: Basic weighted-average common units outstanding 107,789,030 99,490,495 88,825,964 Effect of dilutive potential common units 65,669 40,677 — Diluted weighted-average common units outstanding 107,854,699 99,531,172 88,825,964 Basic and diluted net (loss) income per common unit $ (2.30 ) $ (2.77 ) $ 0.64

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS	12 Months Ended
	Dec. 31, 2019
Statement of Cash Flows [Abstract]
STATEMENTS OF CASH FLOWS	STATEMENTS OF CASH FLOWS Changes in current assets and current liabilities were as follows: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Decrease (increase) in current assets: Accounts receivable $ (23,480 ) $ 22,482 $ (865 ) Receivable from related party — 160 112 Inventories (866 ) 3,819 11,936 Prepaid and other current assets (5,103 ) 3,694 3,393 Increase (decrease) in current liabilities: Accounts payable 8,068 8,003 (30,409 ) Accrued interest payable 1,632 (4,279 ) 6,489 Accrued liabilities (19,614 ) 39,577 (11,157 ) Taxes other than income tax (5,276 ) 4,521 (3,529 ) Income tax payable (126 ) 285 (2,463 ) Changes in current assets and current liabilities $ (44,765 ) $ 78,262 $ (26,493 ) 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; • 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 5 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, 2019 2018 2017 (Thousands of Dollars) Cash paid for interest, net of amount capitalized $ 176,859 $ 183,078 $ 158,089 Cash paid for income taxes, net of tax refunds received $ 6,817 $ 8,535 $ 11,338 As of December 31, 2019 , restricted cash is included in "Other long-term assets, net" on the consolidated balance sheet. “Cash, cash equivalents and restricted cash” on the consolidated statements of cash flows was included in the consolidated balance sheets as follows: December 31, December 31, (Thousands of Dollars) Cash and cash equivalents $ 16,192 $ 11,529 Other long-term assets, net 8,788 — Assets held for sale — 2,115 Cash, cash equivalents and restricted cash $ 24,980 $ 13,644

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	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, 2019 , 2018 and 2017 totaled $7.6 million , $7.4 million and $6.9 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, 2019 , 2018 and 2017 , our costs for these plans totaled $0.9 million , $2.5 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, 2019 and 2018 were as follows: Pension Plans Other Postretirement Benefit Plans 2019 2018 2019 2018 (Thousands of Dollars) Change in benefit obligation: Benefit obligation, January 1 $ 141,833 $ 149,817 $ 10,908 $ 12,410 Service cost 9,549 9,621 431 504 Interest cost 5,480 4,824 453 429 Benefits paid (7,109 ) (7,929 ) (217 ) (255 ) Participant contributions — — 62 87 Actuarial loss (gain) 17,504 (14,500 ) 1,559 (2,267 ) Benefit obligation, December 31 $ 167,257 $ 141,833 $ 13,196 $ 10,908 Change in plan assets: Plan assets at fair value, January 1 $ 126,949 $ 129,878 $ — $ — Actual return on plan assets 28,064 (6,034 ) — — Employer contributions 11,132 11,034 155 168 Benefits paid (7,109 ) (7,929 ) (217 ) (255 ) Participant contributions — — 62 87 Plan assets at fair value, December 31 $ 159,036 $ 126,949 $ — $ — Reconciliation of funded status: Fair value of plan assets at December 31 $ 159,036 $ 126,949 $ — $ — Less: Benefit obligation at December 31 167,257 141,833 13,196 10,908 Funded status at December 31 $ (8,221 ) $ (14,884 ) $ (13,196 ) $ (10,908 ) Amounts recognized in the consolidated balance sheets (a): Accrued liabilities $ (303 ) $ (267 ) $ (368 ) $ (362 ) Other long-term liabilities (7,918 ) (14,617 ) (12,828 ) (10,546 ) Net pension liability $ (8,221 ) $ (14,884 ) $ (13,196 ) $ (10,908 ) (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 accumulated benefit obligation is the present value of benefits earned to date, assuming no future salary increases. The aggregate accumulated benefit obligation for our Pension Plans as of December 31, 2019 and 2018 was $164.2 million and $139.7 million , respectively. As of December 31, 2019 and 2018 , the aggregate accumulated benefit obligation for the Pension Plans exceeded plan assets. 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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Service cost $ 9,549 $ 9,621 $ 8,955 $ 431 $ 504 $ 456 Interest cost 5,480 4,824 4,507 453 429 430 Expected return on plan assets (8,015 ) (7,417 ) (6,411 ) — — — Amortization of prior service credit (2,057 ) (2,057 ) (2,059 ) (1,145 ) (1,145 ) (1,145 ) Amortization of net actuarial loss 846 2,174 1,484 42 214 191 Net periodic benefit cost (income) $ 5,803 $ 7,145 $ 6,476 $ (219 ) $ 2 $ (68 ) 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 income (expense), 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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Net unrecognized gain (loss) arising during the year: Net actuarial gain (loss) $ 2,545 $ 1,049 $ (4,235 ) $ (1,559 ) $ 2,267 $ (590 ) Net (gain) loss reclassified into income: Amortization of prior service credit (2,057 ) (2,057 ) (2,059 ) (1,145 ) (1,145 ) (1,145 ) Amortization of net actuarial loss 846 2,174 1,484 42 214 191 Net (gain) loss reclassified into income (1,211 ) 117 (575 ) (1,103 ) (931 ) (954 ) Reclassification of stranded tax effects — (74 ) — — — — Income tax benefit (expense) 14 (69 ) 162 — (25 ) 22 Total changes to other comprehensive income (loss) $ 1,348 $ 1,023 $ (4,648 ) $ (2,662 ) $ 1,311 $ (1,522 ) 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, 2019 2018 2019 2018 (Thousands of Dollars) Unrecognized actuarial loss $ (24,564 ) $ (27,955 ) $ (3,190 ) $ (1,673 ) Prior service credit 12,490 14,547 7,174 8,319 Deferred tax asset 90 76 — — Accumulated other comprehensive (loss) income, net of tax $ (11,984 ) $ (13,332 ) $ 3,984 $ 6,646 The following pre-tax amounts in AOCI as of December 31, 2019 are expected to be recognized as components of net periodic benefit cost (income) in 2020 : Pension Plans Other Postretirement Benefit Plans (Thousands of Dollars) Actuarial loss $ 1,845 $ 137 Prior service credit $ (2,057 ) $ (1,145 ) 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, 2019 , 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 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. The major classes of plan assets measured at fair value for the Pension Plan were as follows: 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 December 31, 2018 Level 1 Level 2 Level 3 Total (Thousands of Dollars) Cash equivalent securities $ 608 $ — $ — $ 608 Equity securities: U.S. large cap equity fund (a) — 70,525 — 70,525 International stock index fund (b) 13,391 — — 13,391 Fixed income securities: Bond market index fund (c) 42,425 — — 42,425 Total $ 56,424 $ 70,525 $ — $ 126,949 (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, 2019 , we contributed $11.1 million and $0.2 million to the Pension Plans and other postretirement benefit plans, respectively. During 2020 , we expect to contribute approximately $11.3 million and $0.4 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) 2020 $ 9,058 $ 368 2021 $ 9,859 $ 393 2022 $ 9,987 $ 428 2023 $ 10,461 $ 481 2024 $ 10,825 $ 507 Years 2025-2029 $ 59,680 $ 3,232 Assumptions The weighted-average assumptions used to determine the benefit obligations were as follows: Pension Plans Other Postretirement Benefit Plans December 31, December 31, 2019 2018 2019 2018 Discount rate 3.34 % 4.40 % 3.43 % 4.53 % Rate of compensation increase 3.51 % 3.51 % 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, 2019 2018 2017 2019 2018 2017 Discount rate 4.40 % 3.72 % 4.33 % 4.53 % 3.82 % 4.49 % Expected long-term rate of return on plan assets 6.50 % 6.50 % 6.00 % n/a n/a n/a Rate of compensation increase 3.51 % 3.51 % 3.51 % n/a n/a n/a The assumed health care cost trend rates were as follows: December 31, 2019 2018 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. The assumed increase in total health care cost exceeds the 2.5% indexed cap, so increasing or decreasing the health care cost trend rate by 1% does not materially change our obligation or expense for the postretirement health care plan.

UNIT-BASED COMPENSATION

UNIT-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
UNIT-BASED COMPENSATION	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, 2019 , a total of 2,230,392 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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Restricted Units: Domestic employees 1,223,143 1,028,484 736,746 $ 9,437 $ 8,233 $ 7,881 Non-employee directors (NEDs) 61,349 59,752 27,097 774 524 251 International employees 10,243 30,918 58,107 711 1,158 595 Performance Units 161,561 158,326 80,961 4,172 1,889 — Unit Awards — — — 22,846 18,895 — Total 1,456,296 1,277,480 902,911 $ 37,940 $ 30,699 $ 8,727 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 $2.7 million , $2.0 million and $3.0 million respectively, in cash, for the years ended December 31, 2019 , 2018 and December 31, 2017 . 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 . As discussed in Note 3 , on January 1, 2019 we adopted amended guidance that will allow 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, 2019, we granted 5,378 restricted units and 26,053 restricted units vested. A summary of our restricted unit activity for domestic employees and, beginning January 1, 2019, NEDs is as follows: Number of Restricted Units Weighted-Average Grant-Date Fair Value Per Unit Nonvested units as of January 1, 2017 647,340 $ 39.72 Granted 307,009 29.56 Vested (201,466 ) 38.74 Forfeited (16,137 ) 40.00 Nonvested units as of December 31, 2017 736,746 35.95 Converted on July 20, 2018 53,447 24.99 Granted 518,282 24.07 Vested (235,746 ) 35.12 Forfeited (44,245 ) 36.05 Nonvested units as of December 31, 2018 1,028,484 29.47 NEDs 59,752 20.93 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 The total fair value of our equity-classified restricted unit awards vested for the years ended December 31, 2019 , 2018 and 2017 was $9.3 million , $6.2 million and $6.5 million , respectively. We issued 242,199 , 189,399 and 152,017 common units in connection with these award vestings, net of employee tax withholding requirements, for the years ended December 31, 2019 , 2018 and 2017 , respectively. Unrecognized compensation cost related to our equity-classified employee awards totaled $32.5 million as of December 31, 2019 , which we expect to recognize over a weighted-average period of 3.8 years . Performance Units Performance units are issued to certain of our key employees and represent rights to receive our common units upon achieving performance measures for the performance period established by the NuStar GP, LLC Compensation Committee for the following year. Achievement of the performance measures determines the rate at which the performance units convert into our common units, which ranges from zero to 200% for certain awards. Performance units awarded vest in three annual increments (tranches), based upon our achievement of the performance measures set by the Compensation Committee during the one-year performance periods that end on December 31 of each applicable year. Therefore, the performance units are not considered granted for accounting purposes until the Compensation Committee has set the performance measures for each tranche of awards. Performance units are equity-classified awards measured at the grant date fair value. In addition, since the performance units 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. 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 units expected to be converted are recognized as a cumulative adjustment. A summary of our performance units is shown below: Granted for Accounting Purposes Total Performance Units Awarded Performance Units Weighted-Average Grant Date Fair Value per Unit Outstanding as of January 1, 2017 77,014 35,373 $ 31.75 Granted 39,320 38,865 50.04 Performance adjustments (a) 17,690 17,690 31.75 Vested (53,063 ) (53,063 ) 31.75 Outstanding as of December 31, 2017 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 (a) Represents the additional units issued to employees resulting from performance that exceeded the specified targets for the performance measures. For the year ended December 31, 2017 , we issued 33,438 common units in connection with the performance award vestings related to 2016 performance, net of employee tax withholding requirements, and the total fair value of performance awards vested was $2.9 million . For the year ended December 31, 2018 , no performance units vested with respect to 2017 performance. For the year ended December 31, 2019 , we issued 50,054 common units in connection with the performance award vestings related to 2018 performance, net of employee tax withholding requirements, and the total fair value of performance awards vested was $2.1 million . 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 February of the subsequent years. 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 11, 2020 $ 22,846 822,979 563,806 February 11, 2019 $ 17,537 704,886 482,971 July 23, 2018 $ 1,358 55,133 35,745

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	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, 2019 2018 2017 (Thousands of Dollars) Current: U.S. $ 3,741 $ 4,515 $ 3,117 Foreign 1,489 4,658 6,335 Foreign withholding tax 101 192 479 Total current 5,331 9,365 9,931 Deferred: U.S. (490 ) 1,403 1,468 Foreign (168 ) 394 (1,065 ) Foreign withholding tax 182 246 (397 ) Total deferred (476 ) 2,043 6 Less: amounts reported in discontinued operations 101 1,251 2,164 Income tax expense $ 4,754 $ 10,157 $ 7,773 The difference between income tax expense recorded in our consolidated statements of (loss) income and income taxes computed by applying the statutory federal income tax rate ( 21% for 2019 and 2018 and 35% for 2017) 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, 2019 2018 (Thousands of Dollars) Deferred income tax assets: Net operating losses $ 26,081 $ 21,009 Employee benefits 372 362 Environmental and legal reserves 267 239 Allowance for bad debt — 1,970 Capital loss 3,870 — Other 328 1,796 Total deferred income tax assets 30,918 25,376 Less: Valuation allowance (17,743 ) (12,442 ) Net deferred income tax assets 13,175 12,934 Deferred income tax liabilities: Property, plant and equipment (25,169 ) (25,128 ) Foreign withholding tax (433 ) (234 ) Total deferred income tax liabilities (25,602 ) (25,362 ) Net deferred income tax liability $ (12,427 ) $ (12,428 ) Reported on the consolidated balance sheets as: Deferred income tax liability $ (12,427 ) $ (12,428 ) As of December 31, 2019 , our U.S. and foreign corporate operations have net operating loss carryforwards for tax purposes totaling $96.8 million and $19.1 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 can be carried forward indefinitely. As of December 31, 2019 , our U.S. corporate operations have a capital loss carryforward for tax purposes totaling $18.4 million , which is subject to limitations on use and expires in 2024 . As of December 31, 2019 and 2018 , we recorded a valuation allowance of $17.7 million and $12.4 million , respectively, related to our deferred tax assets. 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 2019 , there was a $3.7 million increase in the valuation allowance for the U.S. net operating loss and a $1.6 million increase in the foreign net operating loss valuation allowance due to changes in our estimates of the amount of those loss carryforwards that will be realized, based upon future taxable income. The realization of net deferred income tax assets recorded as of December 31, 2019 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, 2019 will be realized, based on expected future taxable income.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
SEGMENT INFORMATION	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, 2019 2018 2017 (Thousands of Dollars) Revenues: Pipeline $ 701,830 $ 611,065 $ 516,288 Storage: Third parties 453,976 443,546 438,677 Intersegment 25 42 4,339 Total storage 454,001 443,588 443,016 Fuels marketing 342,215 465,651 489,807 Consolidation and intersegment eliminations (25 ) (42 ) (4,339 ) Total revenues $ 1,498,021 $ 1,520,262 $ 1,444,772 Depreciation and amortization expense: Pipeline $ 166,991 $ 153,943 $ 128,061 Storage 97,573 93,345 91,696 Total segment depreciation and amortization expense 264,564 247,288 219,757 Other depreciation and amortization expense 8,360 8,604 8,435 Total depreciation and amortization expense $ 272,924 $ 255,892 $ 228,192 Operating income: Pipeline $ 332,480 $ 272,695 $ 231,795 Storage 154,105 155,708 172,720 Fuels marketing 20,578 15,964 1,987 Consolidation and intersegment eliminations (32 ) 32 (1 ) Total segment operating income 507,131 444,399 406,501 General and administrative expenses 107,855 100,067 107,556 Other depreciation and amortization expense 8,360 8,604 8,435 Total operating income $ 390,916 $ 335,728 $ 290,510 Revenues by geographic area are shown in the table below: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) United States $ 1,465,135 $ 1,481,844 $ 1,406,776 Foreign 32,886 38,418 37,996 Consolidated revenues $ 1,498,021 $ 1,520,262 $ 1,444,772 For the years ended December 31, 2019 , 2018 and 2017 , Valero Energy Corporation accounted for approximately 21% , or $307.2 million , 20% , or $303.7 million , and 20% , or $294.5 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, 2019 2018 (Thousands of Dollars) United States $ 4,000,647 $ 3,688,631 Foreign 118,332 86,171 Consolidated property, plant and equipment, net $ 4,118,979 $ 3,774,802 Total assets by reportable segment were as follows: December 31, 2019 2018 (Thousands of Dollars) Pipeline $ 3,884,819 $ 3,637,226 Storage 2,082,832 1,902,764 Fuels marketing 31,064 37,252 Total segment assets 5,998,715 5,577,242 Assets held for sale — 599,347 Other partnership assets 187,277 172,551 Total consolidated assets $ 6,185,992 $ 6,349,140 Capital expenditures, including acquisitions, by reportable segment were as follows: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Pipeline $ 387,702 $ 288,035 $ 1,596,311 Storage 141,972 202,782 244,398 Other partnership assets 3,894 4,137 5,648 Total capital expenditures $ 533,568 $ 494,954 $ 1,846,357 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 , $114.8 million , and $153.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.

CONDENSED CONSOLIDATING FINANCI

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS	12 Months Ended
	Dec. 31, 2019
CONDENSED CONSOLIDATING FINANCIAL STATEMENTS [Abstract]
CONDENSED CONSOLIDATING FINANCIAL STATEMENTS	CONDENSED CONSOLIDATING FINANCIAL STATEMENTS NuStar Energy has no operations, and its assets consist mainly of its 100% indirectly owned subsidiaries, NuStar Logistics and NuPOP. The senior and subordinated notes issued by NuStar Logistics are fully and unconditionally guaranteed by NuStar Energy and NuPOP. As a result, the following condensed consolidating financial statements are presented as an alternative to providing separate financial statements for NuStar Logistics and NuPOP. Condensed Consolidating Balance Sheets December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Assets Cash and cash equivalents $ 176 $ 24 $ — $ 15,992 $ — $ 16,192 Receivables, net — 317 4 152,209 — 152,530 Inventories — 1,953 4,821 5,619 — 12,393 Prepaid and other current assets 61 16,325 600 4,947 — 21,933 Intercompany receivable — 1,276,839 — 610,298 (1,887,137 ) — Total current assets 237 1,295,458 5,425 789,065 (1,887,137 ) 203,048 Property, plant and equipment, net — 2,058,530 612,128 1,448,321 — 4,118,979 Intangible assets, net — 39,683 — 641,949 — 681,632 Goodwill — 149,453 170,652 685,748 — 1,005,853 Investment in wholly owned subsidiaries 2,871,540 1,743,066 1,155,855 490,826 (6,261,287 ) — Other long-term assets, net 98 111,362 32,121 32,899 — 176,480 Total assets $ 2,871,875 $ 5,397,552 $ 1,976,181 $ 4,088,808 $ (8,148,424 ) $ 6,185,992 Liabilities, Mezzanine Equity and Partners’ Equity Accounts payable $ 5,427 $ 42,064 $ 8,379 $ 53,964 $ — $ 109,834 Short-term debt and current portion of finance leases — 9,722 299 25 — 10,046 Current portion of long-term debt — 452,367 — — — 452,367 Accrued interest payable — 37,888 4 33 — 37,925 Accrued liabilities 1,425 40,514 8,461 53,885 — 104,285 Taxes other than income tax 125 7,311 5,160 185 — 12,781 Income tax payable — 492 2 3,831 — 4,325 Intercompany payable 438,857 — 1,448,280 — (1,887,137 ) — Total current liabilities 445,834 590,358 1,470,585 111,923 (1,887,137 ) 731,563 Long-term debt, less current portion — 2,871,786 1,127 62,005 — 2,934,918 Deferred income tax liability — 1,499 10 10,918 — 12,427 Other long-term liabilities — 65,577 13,774 69,588 — 148,939 Series D preferred units 581,935 — — — — 581,935 Total partners’ equity 1,844,106 1,868,332 490,685 3,834,374 (6,261,287 ) 1,776,210 Total liabilities, mezzanine equity and partners’ equity $ 2,871,875 $ 5,397,552 $ 1,976,181 $ 4,088,808 $ (8,148,424 ) $ 6,185,992 Condensed Consolidating Balance Sheets December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Assets Cash and cash equivalents $ 1,255 $ 51 $ — $ 10,223 $ — $ 11,529 Receivables, net — 2,212 — 108,205 — 110,417 Inventories — 1,741 5,237 1,456 — 8,434 Prepaid and other current assets 61 14,422 908 1,983 — 17,374 Assets held for sale — — — 599,347 — 599,347 Intercompany receivable — 1,327,833 — 500,583 (1,828,416 ) — Total current assets 1,316 1,346,259 6,145 1,221,797 (1,828,416 ) 747,101 Property, plant and equipment, net — 1,858,264 615,549 1,300,989 — 3,774,802 Intangible assets, net — 49,107 — 683,949 — 733,056 Goodwill — 149,453 170,652 685,748 — 1,005,853 Investment in wholly owned subsidiaries 3,355,636 1,750,256 1,425,283 857,485 (7,388,660 ) — Other long-term assets, net 304 54,429 26,716 6,879 — 88,328 Total assets $ 3,357,256 $ 5,207,768 $ 2,244,345 $ 4,756,847 $ (9,217,076 ) $ 6,349,140 Liabilities, Mezzanine Equity and Partners’ Equity Accounts payable $ 6,460 $ 39,680 $ 6,331 $ 50,651 $ — $ 103,122 Short-term debt — 18,500 — — — 18,500 Accrued interest payable — 36,253 — 40 — 36,293 Accrued liabilities 1,280 24,858 8,082 40,198 — 74,418 Taxes other than income tax 125 7,285 4,718 4,695 — 16,823 Income tax payable — 457 2 3,986 — 4,445 Liabilities held for sale — — — 69,834 — 69,834 Intercompany payable 472,790 — 1,355,626 — (1,828,416 ) — Total current liabilities 480,655 127,033 1,374,759 169,404 (1,828,416 ) 323,435 Long-term debt — 3,050,531 — 61,465 — 3,111,996 Deferred income tax liability — 1,675 9 10,744 — 12,428 Other long-term liabilities — 28,392 12,348 38,818 — 79,558 Series D preferred units 563,992 — — — — 563,992 Total partners’ equity 2,312,609 2,000,137 857,229 4,476,416 (7,388,660 ) 2,257,731 Total liabilities, mezzanine equity and partners’ equity $ 3,357,256 $ 5,207,768 $ 2,244,345 $ 4,756,847 $ (9,217,076 ) $ 6,349,140 Condensed Consolidating Statements of (Loss) Income For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 545,863 $ 258,420 $ 694,485 $ (747 ) $ 1,498,021 Costs and expenses 2,574 338,291 159,376 607,611 (747 ) 1,107,105 Operating (loss) income (2,574 ) 207,572 99,044 86,874 — 390,916 Equity in earnings of subsidiaries 208,995 42,139 51,537 144,366 (447,037 ) — Interest income (expense), net 415 (187,337 ) (6,961 ) 10,813 — (183,070 ) Other income (expense), net — 3,002 744 (4 ) — 3,742 Income from continuing operations before income tax expense (benefit) 206,836 65,376 144,364 242,049 (447,037 ) 211,588 Income tax expense (benefit) 2 (230 ) 3 4,979 — 4,754 Income from continuing operations, net of tax 206,834 65,606 144,361 237,070 (447,037 ) 206,834 (Loss) income from discontinued operations, net of tax (a) (312,527 ) 7,912 (320,439 ) (640,877 ) 953,404 (312,527 ) Net (loss) income $ (105,693 ) $ 73,518 $ (176,078 ) $ (403,807 ) $ 506,367 $ (105,693 ) (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations. Condensed Consolidating Statements of Income (Loss) For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 485,603 $ 260,679 $ 774,685 $ (705 ) $ 1,520,262 Costs and expenses 2,407 317,286 163,667 701,879 (705 ) 1,184,534 Operating (loss) income (2,407 ) 168,317 97,012 72,806 — 335,728 Equity in earnings of subsidiaries 148,554 17,167 62,494 152,830 (381,045 ) — Interest income (expense), net 228 (191,835 ) (7,127 ) 14,336 — (184,398 ) Other income, net — 3,876 446 880 — 5,202 Income (loss) from continuing operations before income tax expense (benefit) 146,375 (2,475 ) 152,825 240,852 (381,045 ) 156,532 Income tax expense (benefit) — 588 (3 ) 9,572 — 10,157 Income (loss) from continuing operations, net of tax 146,375 (3,063 ) 152,828 231,280 (381,045 ) 146,375 Income from discontinued operations, net of tax (a) 59,419 — 59,419 118,838 (178,257 ) 59,419 Net income (loss) $ 205,794 $ (3,063 ) $ 212,247 $ 350,118 $ (559,302 ) $ 205,794 (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations. Condensed Consolidating Statements of Income (Loss) For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 496,454 $ 221,125 $ 728,211 $ (1,018 ) $ 1,444,772 Costs and expenses 1,868 317,871 146,243 689,298 (1,018 ) 1,154,262 Operating (loss) income (1,868 ) 178,583 74,882 38,913 — 290,510 Equity in earnings (loss) of subsidiaries 112,706 (10,616 ) 52,336 121,631 (276,057 ) — Interest income (expense), net 57 (176,897 ) (5,587 ) 10,653 — (171,774 ) Other income (expense), net — 145 3 (216 ) — (68 ) Income (loss) from continuing operations before income tax (benefit) expense 110,895 (8,785 ) 121,634 170,981 (276,057 ) 118,668 Income tax (benefit) expense — (820 ) 2 8,591 — 7,773 Income (loss) from continuing operations, net of tax 110,895 (7,965 ) 121,632 162,390 (276,057 ) 110,895 Income from discontinued operations, net of tax (a) 37,069 — 37,069 74,138 (111,207 ) 37,069 Net income (loss) $ 147,964 $ (7,965 ) $ 158,701 $ 236,528 $ (387,264 ) $ 147,964 (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations. Condensed Consolidating Statements of Comprehensive (Loss) Income For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) income $ (105,693 ) $ 73,518 $ (176,078 ) $ (403,807 ) $ 506,367 $ (105,693 ) Other comprehensive income (loss): Foreign currency translation adjustment — — — 3,527 — 3,527 Net loss on pension and other postretirement benefit adjustments, net of tax benefit — — — (1,314 ) — (1,314 ) Net loss on cash flow hedges — (15,231 ) — — — (15,231 ) Total other comprehensive (loss) income — (15,231 ) — 2,213 — (13,018 ) Comprehensive (loss) income $ (105,693 ) $ 58,287 $ (176,078 ) $ (401,594 ) $ 506,367 $ (118,711 ) Condensed Consolidating Statements of Comprehensive Income For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 205,794 $ (3,063 ) $ 212,247 $ 350,118 $ (559,302 ) $ 205,794 Other comprehensive income: Foreign currency translation adjustment — — — 4,304 — 4,304 Net gain on pension and other postretirement benefit adjustments, net of tax expense — — — 2,334 — 2,334 Net gain on cash flow hedges — 23,411 — — — 23,411 Total other comprehensive income — 23,411 — 6,638 — 30,049 Comprehensive income $ 205,794 $ 20,348 $ 212,247 $ 356,756 $ (559,302 ) $ 235,843 Condensed Consolidating Statements of Comprehensive Income (Loss) For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 147,964 $ (7,965 ) $ 158,701 $ 236,528 $ (387,264 ) $ 147,964 Other comprehensive income (loss): Foreign currency translation adjustment — — — 17,466 — 17,466 Net loss on pension and other postretirement benefit adjustments, net of tax benefit — — — (6,170 ) — (6,170 ) Net loss on cash flow hedges — (2,046 ) — — — (2,046 ) Total other comprehensive (loss) income — (2,046 ) — 11,296 — 9,250 Comprehensive income (loss) $ 147,964 $ (10,011 ) $ 158,701 $ 247,824 $ (387,264 ) $ 157,214 Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 376,999 $ 166,005 $ 126,728 $ 409,115 $ (570,090 ) $ 508,757 Cash flows from investing activities: Capital expenditures — (257,117 ) (28,592 ) (247,859 ) — (533,568 ) Change in accounts payable related to capital expenditures — 1,369 1,212 (15,312 ) — (12,731 ) Proceeds from sale or disposition of assets — 247 90 227,815 — 228,152 Investment in subsidiaries — (11,999 ) — — 11,999 — Other, net — — — (1,100 ) — (1,100 ) Net cash used in investing activities — (267,500 ) (27,290 ) (36,456 ) 11,999 (319,247 ) Cash flows from financing activities: Debt borrowings — 1,415,580 — 42,800 — 1,458,380 Debt repayments — (1,207,000 ) — (42,400 ) — (1,249,400 ) Issuance of common units, net of issuance costs 15,000 — — — — 15,000 Distributions to preferred unitholders (121,693 ) (60,846 ) (60,847 ) (60,853 ) 182,546 (121,693 ) Distributions to common unitholders (258,354 ) (129,177 ) (129,177 ) (129,190 ) 387,544 (258,354 ) Contributions from affiliates — — — 11,999 (11,999 ) — Net intercompany activity (2,010 ) 101,980 90,734 (190,704 ) — — Other, net (11,021 ) (10,281 ) (148 ) (133 ) — (21,583 ) Net cash (used in) provided by financing activities (378,078 ) 110,256 (99,438 ) (368,481 ) 558,091 (177,650 ) Effect of foreign exchange rate changes on cash — — — (524 ) — (524 ) Net (decrease) increase in cash, cash equivalents and restricted cash (1,079 ) 8,761 — 3,654 — 11,336 Cash, cash equivalents and restricted cash as of the beginning of the period 1,255 51 — 12,338 — 13,644 Cash, cash equivalents and restricted cash as of the end of the period $ 176 $ 8,812 $ — $ 15,992 $ — $ 24,980 Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 444,233 $ 100,385 $ 179,512 $ 514,936 $ (694,859 ) $ 544,207 Cash flows from investing activities: Capital expenditures — (71,044 ) (19,152 ) (367,256 ) — (457,452 ) Change in accounts payable related to capital expenditures — 11,101 (5,161 ) (13,623 ) — (7,683 ) Acquisitions — — (37,502 ) — — (37,502 ) Proceeds from insurance recoveries — — — 78,419 — 78,419 Proceeds from sale or disposition of assets — 2,674 31 267,735 — 270,440 Investment in subsidiaries (708,600 ) (1,711,975 ) (54,600 ) (54,665 ) 2,529,840 — Net cash used in investing activities (708,600 ) (1,769,244 ) (116,384 ) (89,390 ) 2,529,840 (153,778 ) Cash flows from financing activities: Debt borrowings — 1,840,853 — 31,800 — 1,872,653 Debt repayments — (2,349,476 ) — (32,300 ) — (2,381,776 ) Issuance of Series D preferred units 590,000 — — — — 590,000 Payment of issuance costs for (34,203 ) — — — — (34,203 ) Issuance of common units, net of 10,000 — — — — 10,000 General partner contribution 204 — — — — 204 Distributions to preferred unitholders (90,670 ) (45,336 ) (45,336 ) (45,335 ) 136,007 (90,670 ) Distributions to common unitholders and general partner (300,777 ) (150,388 ) (150,388 ) (150,408 ) 451,184 (300,777 ) Cash consideration for Merger (67,936 ) — — 141 — (67,795 ) Proceeds from termination of interest rate swaps — 8,048 — — — 8,048 Contributions from affiliates — 599,400 54,600 1,768,172 (2,422,172 ) — Net intercompany activity 162,498 1,766,881 77,996 (2,007,375 ) — — Other, net (4,379 ) (1,101 ) — (71 ) — (5,551 ) Net cash provided by (used in) financing activities 264,737 1,668,881 (63,128 ) (435,376 ) (1,834,981 ) (399,867 ) Effect of foreign exchange rate changes on cash — — — (1,210 ) — (1,210 ) Net increase (decrease) in cash and cash equivalents 370 22 — (11,040 ) — (10,648 ) Cash and cash equivalents as of the beginning of the period 885 29 — 23,378 — 24,292 Cash and cash equivalents as of the end of the period $ 1,255 $ 51 $ — $ 12,338 $ — $ 13,644 Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 483,481 $ 152,101 $ 102,405 $ 405,950 $ (737,138 ) $ 406,799 Cash flows from investing activities: Capital expenditures — (47,600 ) (35,041 ) (301,997 ) — (384,638 ) Change in accounts payable related to capital expenditures — (1,988 ) 5,964 32,927 — 36,903 Acquisitions — — — (1,461,719 ) — (1,461,719 ) Proceeds from Axeon term loan — 110,000 — — — 110,000 Proceeds from insurance recoveries — — — 977 — 977 Proceeds from sale or disposition of assets — 1,955 18 63 — 2,036 Investment in subsidiaries (1,262,000 ) — — (126 ) 1,262,126 — Net cash (used in) provided by investing activities (1,262,000 ) 62,367 (29,059 ) (1,729,875 ) 1,262,126 (1,696,441 ) Cash flows from financing activities: Debt borrowings — 2,969,400 — 90,700 — 3,060,100 Debt repayments — (2,400,739 ) — (86,800 ) — (2,487,539 ) Issuance of preferred units, net of 538,560 — — — — 538,560 Issuance of common units, net of 643,878 — — — — 643,878 General partner contribution 13,737 — — — — 13,737 Distributions to preferred unitholders (38,833 ) (19,417 ) (19,416 ) (19,418 ) 58,251 (38,833 ) Distributions to common unitholders and general partner (446,306 ) (223,153 ) (223,153 ) (223,176 ) 669,482 (446,306 ) Contributions from — 1,262,000 — (9,279 ) (1,252,721 ) — Net intercompany activity 73,206 (1,801,218 ) 169,223 1,558,789 — — Other, net (5,708 ) (1,317 ) — (300 ) — (7,325 ) Net cash provided by (used in) financing activities 778,534 (214,444 ) (73,346 ) 1,310,516 (524,988 ) 1,276,272 Effect of foreign exchange rate changes on cash — — — 1,720 — 1,720 Net increase (decrease) in cash and cash equivalents 15 24 — (11,689 ) — (11,650 ) Cash and cash equivalents as of the beginning of the period 870 5 — 35,067 — 35,942 Cash and cash equivalents as of the end of the period $ 885 $ 29 $ — $ 23,378 $ — $ 24,292

QUARTERLY FINANCIAL DATA (UNAUD

QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
QUARTERLY FINANCIAL DATA (UNAUDITED)	QUARTERLY FINANCIAL DATA (UNAUDITED) The following table summarizes quarterly financial data for the years ended December 31, 2019 and 2018 : First Quarter Second Quarter Third Quarter Fourth Quarter Total (Thousands of Dollars, Except Per Unit Data) 2019: Revenues $ 347,826 $ 372,445 $ 378,056 $ 399,694 $ 1,498,021 Operating income $ 73,605 $ 93,283 $ 99,972 $ 124,056 $ 390,916 Income from continuing operations, net of tax $ 28,923 $ 46,915 $ 52,588 $ 78,408 $ 206,834 Loss from discontinued operations, net of tax (306,786 ) (964 ) (4,777 ) — (312,527 ) Net (loss) income $ (277,863 ) $ 45,951 $ 47,811 $ 78,408 $ (105,693 ) Basic and diluted net (loss) income per common unit: Continuing operations $ (0.06 ) $ 0.11 $ 0.15 $ 0.40 $ 0.60 Discontinued operations (2.85 ) (0.01 ) (0.04 ) — (2.90 ) Total $ (2.91 ) $ 0.10 $ 0.11 $ 0.40 $ (2.30 ) Cash distributions per unit applicable to common limited partners $ 0.60 $ 0.60 $ 0.60 $ 0.60 $ 2.40 2018: Revenues $ 376,727 $ 389,256 $ 380,142 $ 374,137 $ 1,520,262 Operating income $ 83,493 $ 76,387 $ 89,165 $ 86,683 $ 335,728 Income from continuing operations, net of tax $ 33,233 $ 26,909 $ 43,663 $ 42,570 $ 146,375 Income (loss) from discontinued operations, net of tax 92,900 2,490 4,473 (40,444 ) 59,419 Net income $ 126,133 $ 29,399 $ 48,136 $ 2,126 $ 205,794 Basic and diluted net income (loss) per common unit: Continuing operations $ 0.18 $ 0.12 $ (3.53 ) $ 0.07 $ (3.34 ) Discontinued operations 0.97 0.03 0.04 (0.38 ) 0.57 Total $ 1.15 $ 0.15 $ (3.49 ) $ (0.31 ) $ (2.77 ) Cash distributions per unit applicable to common limited partners $ 0.60 $ 0.60 $ 0.60 $ 0.60 $ 2.40 The quarterly financial data in the table above includes the following: • impairment and goodwill losses of $297.3 million and $31.1 million , respectively, in the first quarter of 2019 (please refer to Note 5 for further discussion); • the $43.4 million non-cash loss associated with the sale of our European Operations in the fourth quarter of 2018 (please refer to Note 5 for further discussion); and • the $78.8 million gain from hurricane insurance proceeds received in the first quarter of 2018 (please refer to Note 1 for further discussion). Basic and diluted net income (loss) per common unit also includes the impact of the $377.1 million loss as a result of the Merger in 2018. Please refer to Notes 4 and 21 for further discussion.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2019
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 Equivalents
Accounts Receivable	Accounts Receivable Trade receivables are carried at original invoice amount. We extend credit terms to certain customers after review of various credit indicators, including the customer’s credit rating. Outstanding customer receivable balances are regularly reviewed for possible non-payment indicators and allowances for doubtful accounts are 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, except those associated with a qualifying fair value hedge, 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. Inventories associated with qualifying fair value hedges are valued at current market prices. Materials and supplies are valued at the lower of average cost or net realizable value.
Restricted Cash	Restricted Cash As of December 31, 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 income (expense), 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 performed a qualitative assessment as of October 1, 2019 . Our qualitative assessment included, among other things, industry and market considerations, overall financial performance, other entity-specific events and events affecting individual reporting units. After assessing the totality of events or circumstances for each reporting unit, we determined that the carrying value did not exceed its fair value and that goodwill was not impaired. Our reporting units to which goodwill has been allocated consist of the following as of October 1, 2019: • crude oil pipelines; • refined product pipelines; and • terminals, excluding our Point Tupper facility and our refinery crude storage tanks. As discussed in Note 5 , we recognized a goodwill impairment charge in the first quarter of 2019 for the goodwill associated with the Statia Bunkering reporting unit, which consisted of our bunkering operations at the St. Eustatius terminal facility. 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. See Note 3 for a discussion of new accounting pronouncements. 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. We recognize an impairment of goodwill if the carrying value of goodwill exceeds its estimated fair value. 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 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. We performed a quantitative goodwill impairment test as of October 1, 2018 and determined that no impairment charges existed on that date.
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 5 , 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, 2019 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, 2019 and 2018 . 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 2018, 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. We have recorded liabilities of $0.2 million as of December 31, 2019 and 2018 , which are included in “Other long-term liabilities” in the consolidated balance sheets, for conditional asset retirement obligations related to the retirement of terminal assets with lease and right-of-way agreements.
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 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. Adoption of ASC Topic 606. On January 1, 2018, we adopted Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (ASC Topic 606) using the modified retrospective method and applied ASC Topic 606 to all revenue contracts with customers. After identifying a contract with a customer, ASC Topic 606 requires us to (i) identify the performance obligations in the contract; (ii) determine the transaction price; (iii) allocate the transaction price to the performance obligations; and (iv) recognize revenue when or as we satisfy a performance obligation. 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. Similarly, 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). 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. 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 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, it becomes 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 4 for further discussion of the merger and Note 20 for the calculation of net income applicable to the general partner prior to 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 24 for additional information on our performance units, Note 19 for additional information on our Series D Preferred Units and Note 21 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. Under the terms of our forward-starting interest rate swap agreements, we pay a fixed rate and receive a variable rate. We entered 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 the effective portion of mark-to-market adjustments as a component of accumulated other comprehensive income (loss) (AOCI), and any hedge ineffectiveness is recognized immediately in “Interest expense, net.” 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 18 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 24 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 income (expense), net” or “(Loss) income from discontinued operations, net of tax” in the consolidated statements of (loss) income.
Reclassifications	Reclassifications We have reclassified certain previously reported amounts in the consolidated financial statements and notes to conform to current-period presentation. As further discussed in Note 5

LEASE ASSETS AND LIABILITIES (P

LEASE ASSETS AND LIABILITIES (Policies)	12 Months Ended
	Dec. 31, 2019
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.

MERGER AND RELATED PARTY AGRE_2

MERGER AND RELATED PARTY AGREEMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
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 )

DISCONTINUED OPERATIONS AND I_2

DISCONTINUED OPERATIONS AND IMPAIRMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
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 2017 (Thousands of Dollars) Revenues $ 248,981 $ 441,495 $ 369,247 Costs and expenses: Cost of revenues 220,595 407,256 318,532 Impairment losses 336,838 — — General and administrative expenses (excluding depreciation and amortization expense) 1,231 6,133 4,684 Other depreciation and amortization expense — 271 263 Total costs and expenses 558,664 413,660 323,479 Operating (loss) income (309,683 ) 27,835 45,768 Interest income (expense), net 32 (1,839 ) (1,309 ) Other (expense) income, net (2,775 ) 34,674 (5,226 ) (Loss) income from discontinued operations before income tax expense (312,426 ) 60,670 39,233 Income tax expense 101 1,251 2,164 (Loss) income from discontinued operations, net of tax $ (312,527 ) $ 59,419 $ 37,069
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 2017 (Thousands of Dollars) Capital expenditures $ (27,954 ) $ (114,811 ) $ (153,785 ) Significant noncash operating activities and other adjustments: Depreciation and amortization expense $ 8,536 $ 41,982 $ 36,040 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 ) $ —
Disposal Groups, Including Discontinued Operations [Table Text Block]	The following is a reconciliation of the carrying amounts of the major classes of assets and liabilities included in “Assets held for sale” and “Liabilities held for sale” on the consolidated balance sheet: December 31, 2018 (Thousands of Dollars) Total current assets $ 54,404 Property, plant and equipment, net 513,820 Goodwill 31,123 Assets held for sale $ 599,347 Current liabilities $ 69,834

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table reflects the final purchase price allocation: Purchase Price Allocation (Thousands of Dollars) Accounts receivable $ 4,747 Other current assets 2,359 Property, plant and equipment, net 376,690 Intangible assets (a) 700,000 Goodwill (b) 398,024 Other long-term assets, net 2,199 Current liabilities (22,300 ) Purchase price allocation, net of cash acquired $ 1,461,719 (a) Intangible assets, which consist of customer contracts and relationships, are amortized on a straight-line basis over a period of 20 years . (b) The goodwill acquired represents the expected benefit from entering new geographic areas and the anticipated opportunities to generate future cash flows from the assets acquired and potential future projects.
Business Acquisition, Pro Forma Information [Table Text Block]	The unaudited pro forma information for the year ended December 31, 2017 below presents the combined historical financial information for Navigator and the Partnership for those periods. This information assumes: • we completed the Navigator Acquisition on January 1, 2017; • we issued approximately 14.4 million common units; • we received a contribution from our general partner of $13.6 million to maintain the 2% general partner economic interest it owned at that time; • we issued 15.4 million Series B Preferred Units; • we issued $550.0 million of 5.625% senior notes; • additional depreciation and amortization that would have been incurred assuming the fair value adjustments to property, plant and equipment and intangible assets reflected in the purchase price allocation above; and • we satisfied Navigator’s outstanding obligations under its revolving credit agreement. Year Ended December 31, 2017 (Thousands of Dollars, Except Per Unit Data) Revenues $ 1,828,418 Net income $ 127,433 Basic and diluted net income per common unit $ 0.31 The pro forma information for the year ended December 31, 2017 includes transaction costs of $14.1 million , which were directly attributable to the Navigator Acquisition. The pro forma information is unaudited and is not necessarily indicative of the results of operations that would have resulted had the Navigator Acquisition occurred on January 1, 2017 or that may result in the future.

REVENUE FROM CONTRACTS WITH C_2

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Adoption of New Accounting Pronouncements [Table Text Block]	The adoption of ASC Topic 606 affected our consolidated statements of (loss) income as follows: As Reported Without Adoption of ASC Topic 606 Effect of Change Higher/(Lower) (Thousands of Dollars, Except Per Unit Data) For the year ended December 31, 2018: Revenues $ 1,520,262 $ 1,526,447 $ (6,185 ) Operating income $ 335,728 $ 341,913 $ (6,185 ) Income from continuing operations $ 146,375 $ 152,560 $ (6,185 ) Basic net loss per common unit from continuing operations $ (3.34 ) $ (3.27 ) $ (0.07 )
Contract with Customer, Asset and Liability [Table Text Block]	The following table provides information about contract assets and contract liabilities from contracts with customers: 2019 2018 Contract Assets Contract Liabilities Contract Assets Contract Liabilities (Thousands of Dollars) (Thousands of Dollars) Balances as of January 1: Current portion $ 2,066 $ (21,579 ) $ 1,956 $ (13,801 ) Noncurrent portion 539 (38,945 ) 171 (46,361 ) Held for sale — (25,357 ) — (302 ) Total 2,605 (85,881 ) 2,127 (60,464 ) Activity: Additions 4,890 (52,957 ) 3,281 (83,243 ) Transfer to accounts receivable (4,352 ) — (2,803 ) — Transfer to revenues, including amounts reported in discontinued operations — 77,466 — 57,826 Total 538 24,509 478 (25,417 ) Balances as of December 31: Current portion 2,140 (21,083 ) 2,066 (21,579 ) Noncurrent portion 1,003 (40,289 ) 539 (38,945 ) Held for sale — — — (25,357 ) Total $ 3,143 $ (61,372 ) $ 2,605 $ (85,881 )
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	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, 2019 (in thousands of dollars): 2020 $ 529,830 2021 376,500 2022 310,632 2023 236,853 2024 175,358 Thereafter 255,808 Total $ 1,884,981
Disaggregation of Revenue [Table Text Block]	The following table disaggregates our revenues: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Pipeline segment: Crude oil pipelines $ 316,417 $ 248,261 $ 187,874 Refined products and ammonia pipelines (excluding lessor revenues) 376,588 362,750 328,414 Total pipeline segment revenues from contracts with customers 693,005 611,011 516,288 Lessor revenues 8,825 54 — Total pipeline segment revenues 701,830 611,065 516,288 Storage segment: Throughput terminals 114,243 83,157 85,927 Storage terminals (excluding lessor revenues) 298,984 320,582 317,963 Total storage segment revenues from contracts with customers 413,227 403,739 403,890 Lessor revenues 40,774 39,849 39,126 Total storage segment revenues 454,001 443,588 443,016 Fuels marketing segment: Revenues from contracts with customers 342,215 465,651 489,807 Consolidation and intersegment eliminations (25 ) (42 ) (4,339 ) Total revenues $ 1,498,021 $ 1,520,262 $ 1,444,772

ALLOWANCE FOR DOUBTFUL ACCOUN_2

ALLOWANCE FOR DOUBTFUL ACCOUNTS (Tables)	12 Months Ended
	Dec. 31, 2019
Accounts Receivable Additional Disclosures [Abstract]
Allowance for Doubtful Accounts [Table Text Block]	The changes in the allowance for doubtful accounts consisted of the following: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Balance as of beginning of year $ 9,412 $ 9,380 $ 7,700 Increase in allowance, net 2,322 233 1,705 Accounts charged against the allowance (11,662 ) (201 ) (25 ) Balance as of end of year $ 72 $ 9,412 $ 9,380

INVENTORIES (Tables)

INVENTORIES (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory Table [Text Block]	Inventories consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Petroleum products $ 8,646 $ 4,853 Materials and supplies 3,747 3,581 Total $ 12,393 $ 8,434

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 2018 (Years) (Thousands of Dollars) Land - $ 144,409 $ 138,487 Land and leasehold improvements 5 - 40 223,220 181,578 Buildings 15 - 40 166,878 146,517 Pipelines, storage and terminals 15 - 40 5,038,468 4,702,421 Rights-of-way 20 - 40 350,026 301,738 Construction in progress - 264,143 157,064 Total 6,187,144 5,627,805 Less accumulated depreciation and amortization (2,068,165 ) (1,853,003 ) Property, plant and equipment, net $ 4,118,979 $ 3,774,802

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 December 31, 2018 Cost Accumulated Amortization Cost Accumulated Amortization (Years) (Thousands of Dollars) Customer contracts and relationships 18 $ 863,900 $ (183,832 ) $ 863,950 $ (132,509 ) Other 47 2,359 (795 ) 2,359 (744 ) Total $ 866,259 $ (184,627 ) $ 866,309 $ (133,253 )

GOODWILL (Tables)

GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	Changes in the carrying amount of goodwill by segment were as follows: Pipeline Storage Total (Thousands of Dollars) Balances as of January 1, 2018 $ 707,045 $ 301,622 $ 1,008,667 Activity for the year ended December 31, 2018: Navigator Acquisition purchase price allocation adjustments (Note 6) (2,814 ) — (2,814 ) Balances as of December 31, 2018 and 2019 $ 704,231 $ 301,622 $ 1,005,853

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2019
Accrued Liabilities, Current [Abstract]
Schedule of Accrued Liabilities [Table Text Block]	Accrued liabilities consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Employee wages and benefit costs $ 36,704 $ 29,518 Revenue contract liabilities 21,083 21,579 Interest rate swaps 19,169 — Operating lease liabilities 10,416 — Other 16,913 23,321 Accrued liabilities $ 104,285 $ 74,418

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Short-term Debt [Table Text Block]	Short-term debt consisted of the following: December 31, 2019 2018 (Thousands of Dollars) Short-term line of credit $ 5,500 $ 18,500 Current portion of finance leases (refer to Note 17) 4,546 — Short-term debt and current portion of finance leases $ 10,046 $ 18,500
Schedule of Long-term Debt Instruments [Table Text Block]	Long-term debt consisted of the following: December 31, Maturity 2019 2018 (Thousands of Dollars) Revolving Credit Agreement 2021 $ 475,000 $ 745,000 4.80% senior notes 2020 450,000 450,000 6.75% senior notes 2021 300,000 300,000 4.75% senior notes 2022 250,000 250,000 6.00% senior notes 2026 500,000 — 5.625% senior notes 2027 550,000 550,000 Subordinated Notes 2043 402,500 402,500 GoZone Bonds 2038 thru 2041 365,440 365,440 Receivables Financing Agreement 2021 62,200 61,800 Net fair value adjustments, unamortized discounts and unamortized debt issuance costs N/A (23,301 ) (12,744 ) Total long-term debt (excluding finance leases) 3,331,839 3,111,996 Finance leases (refer to Note 17) 55,446 — Less current portion 452,367 — Long-term debt, less current portion $ 2,934,918 $ 3,111,996
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): 2020 $ 450,000 2021 837,200 2022 250,000 2023 — 2024 — Thereafter 1,817,940 Total repayments 3,355,140 Net fair value adjustments, unamortized discounts and unamortized debt issuance costs (23,301 ) Total long-term debt (excluding finance leases) $ 3,331,839
Schedule of GoZone Bonds [Table Text Block]	The following table summarizes the GoZone Bonds outstanding as of December 31, 2019 : Date Issued Maturity Date Amount Outstanding Amount of Letter of Credit Amount Received from Trustee Amount Remaining in Trust (a) Interest Rate (b) (Thousands of Dollars) June 26, 2008 June 1, 2038 $ 55,440 $ 56,169 $ 55,440 $ — 1.6 % July 15, 2010 July 1, 2040 100,000 101,315 100,000 — 1.5 % October 7, 2010 October 1, 2040 50,000 50,658 43,741 6,652 1.5 % December 29, 2010 December 1, 2040 85,000 86,118 49,782 36,580 1.5 % August 9, 2011 August 1, 2041 75,000 75,986 75,000 — 1.6 % Total $ 365,440 $ 370,246 $ 323,963 $ 43,232 (a) Amount remaining in trust includes accrued interest. (b) For the year ended December 31, 2019 , our weighted-average interest rate on borrowings was 1.5% .

HEALTH, SAFETY AND ENVIRONMEN_2

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 2018 (Thousands of Dollars) Balance as of the beginning of year $ 7,753 $ 5,095 Additions to accrual 3,700 5,708 Payments (3,515 ) (3,050 ) Balance as of the end of year $ 7,938 $ 7,753
Environmental Accruals By Balance Sheet Location [Table Text Block]	Accruals for environmental matters are included in the consolidated balance sheets as follows: December 31, 2019 2018 (Thousands of Dollars) Accrued liabilities $ 4,837 $ 4,349 Other long-term liabilities 3,101 3,404 Accruals for environmental matters $ 7,938 $ 7,753

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 are as follows: Payments Due by Period 2020 2021 2022 2023 2024 There- after Total (Thousands of Dollars) Purchase obligations $ 8,935 $ 7,643 $ 6,202 $ 1,485 $ 812 $ 5,157 $ 30,234

LEASE ASSETS AND LIABILITIES (T

LEASE ASSETS AND LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2019
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: Balance Sheet Location December 31, 2019 (Thousands of Dollars) Right-of-Use Assets: Operating Other long-term assets, net $ 81,219 Finance Property, plant and equipment, net of accumulated amortization of $3,748 $ 74,953 Lease Liabilities: Operating: Current Accrued liabilities $ 10,416 Noncurrent Other long-term liabilities 70,083 Total operating lease liabilities $ 80,499 Finance: Current Short-term debt and current portion of finance leases $ 4,546 Noncurrent Long-term debt, less current portion 55,446 Total finance lease liabilities $ 59,992
Maturity Analysis of Lease Liabilities	As of December 31, 2019 , maturities of our operating and finance lease liabilities were as follows: Operating Leases Finance Leases (Thousands of Dollars) 2020 $ 12,647 $ 6,702 2021 9,419 5,252 2022 8,717 4,582 2023 7,605 4,480 2024 6,739 4,067 Thereafter 60,354 59,681 Total lease payments $ 105,481 $ 84,764 Less: Interest 24,982 24,772 Present value of lease liabilities $ 80,499 $ 59,992
Lease Cost	Costs incurred for leases, including costs associated with discontinued operations, were as follows: Year Ended December 31, 2019 (Thousands of Dollars) Operating lease cost $ 29,167 Finance lease cost: Amortization of right-of-use assets 3,748 Interest expense on lease liability 2,212 Short-term lease cost 19,140 Variable lease cost 6,990 Total lease cost $ 61,257
Additional Lease Information	The table below presents additional information regarding our leases: Operating Leases Finance Leases (Thousands of Dollars, Except Term and Rate Data) For the year ended December 31, 2019: Cash outflows from operating activities $ 27,567 $ 2,027 Cash outflows from financing activities $ — $ 3,700 Right-of-use assets obtained in exchange for lease liabilities $ 2,153 $ 4,430 As of December 31, 2019: Weighted-average remaining lease term (in years) 15 20 Weighted-average discount rate 3.6 % 3.7 %

DERIVATIVES AND FAIR VALUE ME_2

DERIVATIVES AND FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Unwound Interest Rate Swap Agreements [Table Text Block]	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 2019 2018 (Thousands of Dollars) Fixed-to-floating Current portion of long-term debt $ 2,755 $ — Fixed-to-floating Long-term debt, less current portion $ 2,568 $ 10,475 Forward-starting Accumulated other comprehensive income (loss) $ 3,045 $ (770 )
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The fair values of our interest rate swap agreements included in our consolidated balance sheets were as follows: Balance Sheet Location December 31, 2019 2018 (Thousands of Dollars) Other long-term assets, net $ — $ 627 Accrued liabilities $ (19,169 ) $ — Other long-term liabilities $ — $ (751 )
Derivative Instruments, Gain (Loss) [Table Text Block]	Our forward-starting interest rate swaps had the following impact on earnings: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) (Loss) gain recognized in other comprehensive income (loss) on derivative $ (19,045 ) $ 17,912 $ (8,670 ) Loss reclassified from AOCI into interest expense, net $ (3,814 ) $ (5,499 ) $ (6,624 )
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, 2019 December 31, 2018 (Thousands of Dollars) Fair value $ 3,442,001 $ 3,056,704 Carrying amount $ 3,331,839 $ 3,111,996

PARTNERS' EQUITY (Tables)

PARTNERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2019
Distributions Made to Limited Partners and General Partner [Line Items]
Schedule of Preferred Units [Table Text Block]	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, 2019 : Units Original Issuance Date Number of Units Issued and Outstanding Price per Unit Net Proceeds (in millions) 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 $ 218.4 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 $ 371.8 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 $ 166.7 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, 2019 2018 2017 Balance as of the beginning of year 107,225,156 93,176,683 78,616,228 Issuance of units 527,426 413,736 14,375,000 Unit-based compensation (refer to Note 24 for discussion) 775,224 225,144 185,455 Merger (refer to Note 4 for discussion) — 13,409,593 — Balance as of the end of year 108,527,806 107,225,156 93,176,683
Schedule of Distribution Waterfall [Table Text Block]	Prior to the Merger, our Available Cash was distributed based on the percentages shown below: Percentage of Distribution Quarterly Distribution Amount Per Common Unit Common Unitholders General Partner Including Incentive Distributions Up to $0.60 98% 2% Above $0.60 up to $0.66 90% 10% Above $0.66 75% 25%
Schedule of Distributions to General and Common Limited Partners [Table Text Block]	The following table reflects the allocation of total cash distributions to the general partner and common limited partners applicable to the period in which the distributions were earned: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars, Except Per Unit Data) General partner interest $ — $ 1,141 $ 9,252 General partner incentive distribution — — 45,669 Total general partner distribution — 1,141 54,921 Common limited partners’ distribution 259,136 248,705 407,681 Total cash distributions $ 259,136 $ 249,846 $ 462,602 Cash distributions per unit applicable to common limited partners $ 2.40 $ 2.40 $ 4.38
Schedule of Calculation of Net Income Applicable to General Partner [Table Text Block]	The following table details the calculation of net income applicable to the general partner for 2017: Year Ended December 31, 2017 (Thousands of Dollars) Net income attributable to NuStar Energy L.P. $ 147,964 Less preferred limited partner interest 40,448 Less general partner incentive distribution 45,669 Net income after general partner incentive distribution and preferred limited partner interest 61,847 General partner interest allocation 2 % General partner interest allocation of net income 1,237 General partner incentive distribution 45,669 Net income applicable to general partner $ 46,906
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, 2017 $ (69,069 ) $ (22,258 ) $ (2,850 ) $ (94,177 ) Other comprehensive income (loss) before reclassification adjustments 17,466 (8,670 ) (4,641 ) 4,155 Net gain on pension costs reclassified into operating expense — — (1,143 ) (1,143 ) Net gain on pension costs reclassified into general and administrative expense — — (386 ) (386 ) Net loss on cash flow hedges reclassified into interest expense, net — 6,624 — 6,624 Other comprehensive income (loss) 17,466 (2,046 ) (6,170 ) 9,250 Balance as of December 31, 2017 (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 )
Common Limited Partner [Member]
Distributions Made to Limited Partners and General Partner [Line Items]
Distributions Made to Limited Partner, by Distribution [Table Text Block]	The following table summarizes information about quarterly cash distributions declared for our common limited partners applicable to the year ended December 31, 2019 : Quarter Ended Cash Distributions Per Unit Total Cash Distributions Record Date Payment Date (Thousands of Dollars) December 31, 2019 $ 0.60 $ 65,128 February 10, 2020 February 14, 2020 September 30, 2019 $ 0.60 $ 64,660 November 8, 2019 November 14, 2019 June 30, 2019 $ 0.60 $ 64,658 August 7, 2019 August 13, 2019 March 31, 2019 $ 0.60 $ 64,690 May 8, 2019 May 14, 2019

NET (LOSS) INCOME PER COMMON _2

NET (LOSS) INCOME PER COMMON UNIT (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Net (Loss) Income Per Unit [Text Block]	The following table details the calculation of net (loss) income per common unit: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars, Except Unit and Per Unit Data) Net (loss) income $ (105,693 ) $ 205,794 $ 147,964 Distributions to preferred limited partners (121,693 ) (92,540 ) (40,448 ) Distributions to general partner (including incentive distribution rights) — (1,141 ) (54,921 ) Distributions to common limited partners (259,136 ) (248,705 ) (407,681 ) Distribution equivalent rights to restricted units (2,659 ) (2,045 ) (2,965 ) Distributions in excess of (loss) income $ (489,181 ) $ (138,637 ) $ (358,051 ) Distributions to common limited partners $ 259,136 $ 248,705 $ 407,681 Allocation of distributions in excess of (loss) income (489,181 ) (138,659 ) (350,890 ) Series D Preferred Unit accretion (refer to Note 19) (18,085 ) (8,195 ) — Loss to common unitholders attributable to the Merger (refer to Note 4) — (377,079 ) — Net (loss) income attributable to common units $ (248,130 ) $ (275,228 ) $ 56,791 Basic weighted-average common units outstanding 107,789,030 99,490,495 88,825,964 Diluted common units outstanding: Basic weighted-average common units outstanding 107,789,030 99,490,495 88,825,964 Effect of dilutive potential common units 65,669 40,677 — Diluted weighted-average common units outstanding 107,854,699 99,531,172 88,825,964 Basic and diluted net (loss) income per common unit $ (2.30 ) $ (2.77 ) $ 0.64

STATEMENTS OF CASH FLOWS (Table

STATEMENTS OF CASH FLOWS (Tables)	12 Months Ended
	Dec. 31, 2019
Statement of Cash Flows [Abstract]
Schedule of Changes in Current Assets and Liabilities [Text Block]	Changes in current assets and current liabilities were as follows: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Decrease (increase) in current assets: Accounts receivable $ (23,480 ) $ 22,482 $ (865 ) Receivable from related party — 160 112 Inventories (866 ) 3,819 11,936 Prepaid and other current assets (5,103 ) 3,694 3,393 Increase (decrease) in current liabilities: Accounts payable 8,068 8,003 (30,409 ) Accrued interest payable 1,632 (4,279 ) 6,489 Accrued liabilities (19,614 ) 39,577 (11,157 ) Taxes other than income tax (5,276 ) 4,521 (3,529 ) Income tax payable (126 ) 285 (2,463 ) Changes in current assets and current liabilities $ (44,765 ) $ 78,262 $ (26,493 )
Schedule of Supplemental Cash Flow Information [Text Block]	Cash flows related to interest and income taxes were as follows: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Cash paid for interest, net of amount capitalized $ 176,859 $ 183,078 $ 158,089 Cash paid for income taxes, net of tax refunds received $ 6,817 $ 8,535 $ 11,338 As of December 31, 2019 , restricted cash is included in "Other long-term assets, net" on the consolidated balance sheet. “Cash, cash equivalents and restricted cash” on the consolidated statements of cash flows was included in the consolidated balance sheets as follows: December 31, December 31, (Thousands of Dollars) Cash and cash equivalents $ 16,192 $ 11,529 Other long-term assets, net 8,788 — Assets held for sale — 2,115 Cash, cash equivalents and restricted cash $ 24,980 $ 13,644

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Disclosures for our Pension Plans and other postretirement benefit 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, 2019 and 2018 were as follows: Pension Plans Other Postretirement Benefit Plans 2019 2018 2019 2018 (Thousands of Dollars) Change in benefit obligation: Benefit obligation, January 1 $ 141,833 $ 149,817 $ 10,908 $ 12,410 Service cost 9,549 9,621 431 504 Interest cost 5,480 4,824 453 429 Benefits paid (7,109 ) (7,929 ) (217 ) (255 ) Participant contributions — — 62 87 Actuarial loss (gain) 17,504 (14,500 ) 1,559 (2,267 ) Benefit obligation, December 31 $ 167,257 $ 141,833 $ 13,196 $ 10,908 Change in plan assets: Plan assets at fair value, January 1 $ 126,949 $ 129,878 $ — $ — Actual return on plan assets 28,064 (6,034 ) — — Employer contributions 11,132 11,034 155 168 Benefits paid (7,109 ) (7,929 ) (217 ) (255 ) Participant contributions — — 62 87 Plan assets at fair value, December 31 $ 159,036 $ 126,949 $ — $ — Reconciliation of funded status: Fair value of plan assets at December 31 $ 159,036 $ 126,949 $ — $ — Less: Benefit obligation at December 31 167,257 141,833 13,196 10,908 Funded status at December 31 $ (8,221 ) $ (14,884 ) $ (13,196 ) $ (10,908 ) Amounts recognized in the consolidated balance sheets (a): Accrued liabilities $ (303 ) $ (267 ) $ (368 ) $ (362 ) Other long-term liabilities (7,918 ) (14,617 ) (12,828 ) (10,546 ) Net pension liability $ (8,221 ) $ (14,884 ) $ (13,196 ) $ (10,908 ) (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 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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Service cost $ 9,549 $ 9,621 $ 8,955 $ 431 $ 504 $ 456 Interest cost 5,480 4,824 4,507 453 429 430 Expected return on plan assets (8,015 ) (7,417 ) (6,411 ) — — — Amortization of prior service credit (2,057 ) (2,057 ) (2,059 ) (1,145 ) (1,145 ) (1,145 ) Amortization of net actuarial loss 846 2,174 1,484 42 214 191 Net periodic benefit cost (income) $ 5,803 $ 7,145 $ 6,476 $ (219 ) $ 2 $ (68 )
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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Net unrecognized gain (loss) arising during the year: Net actuarial gain (loss) $ 2,545 $ 1,049 $ (4,235 ) $ (1,559 ) $ 2,267 $ (590 ) Net (gain) loss reclassified into income: Amortization of prior service credit (2,057 ) (2,057 ) (2,059 ) (1,145 ) (1,145 ) (1,145 ) Amortization of net actuarial loss 846 2,174 1,484 42 214 191 Net (gain) loss reclassified into income (1,211 ) 117 (575 ) (1,103 ) (931 ) (954 ) Reclassification of stranded tax effects — (74 ) — — — — Income tax benefit (expense) 14 (69 ) 162 — (25 ) 22 Total changes to other comprehensive income (loss) $ 1,348 $ 1,023 $ (4,648 ) $ (2,662 ) $ 1,311 $ (1,522 )
The amounts recorded as a component of accumulated other comprehensive (loss) income	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, 2019 2018 2019 2018 (Thousands of Dollars) Unrecognized actuarial loss $ (24,564 ) $ (27,955 ) $ (3,190 ) $ (1,673 ) Prior service credit 12,490 14,547 7,174 8,319 Deferred tax asset 90 76 — — Accumulated other comprehensive (loss) income, net of tax $ (11,984 ) $ (13,332 ) $ 3,984 $ 6,646
Schedule of pre-tax amounts in accumulated other comprehensive loss to be recognized over next fiscal year	The following pre-tax amounts in AOCI as of December 31, 2019 are expected to be recognized as components of net periodic benefit cost (income) in 2020 : Pension Plans Other Postretirement Benefit Plans (Thousands of Dollars) Actuarial loss $ 1,845 $ 137 Prior service credit $ (2,057 ) $ (1,145 )
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, 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 December 31, 2018 Level 1 Level 2 Level 3 Total (Thousands of Dollars) Cash equivalent securities $ 608 $ — $ — $ 608 Equity securities: U.S. large cap equity fund (a) — 70,525 — 70,525 International stock index fund (b) 13,391 — — 13,391 Fixed income securities: Bond market index fund (c) 42,425 — — 42,425 Total $ 56,424 $ 70,525 $ — $ 126,949 (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.
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) 2020 $ 9,058 $ 368 2021 $ 9,859 $ 393 2022 $ 9,987 $ 428 2023 $ 10,461 $ 481 2024 $ 10,825 $ 507 Years 2025-2029 $ 59,680 $ 3,232
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, 2019 2018 2019 2018 Discount rate 3.34 % 4.40 % 3.43 % 4.53 % Rate of compensation increase 3.51 % 3.51 % 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, 2019 2018 2017 2019 2018 2017 Discount rate 4.40 % 3.72 % 4.33 % 4.53 % 3.82 % 4.49 % Expected long-term rate of return on plan assets 6.50 % 6.50 % 6.00 % n/a n/a n/a Rate of compensation increase 3.51 % 3.51 % 3.51 % 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, 2019 2018 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

UNIT-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 2018 2017 2019 2018 2017 (Thousands of Dollars) Restricted Units: Domestic employees 1,223,143 1,028,484 736,746 $ 9,437 $ 8,233 $ 7,881 Non-employee directors (NEDs) 61,349 59,752 27,097 774 524 251 International employees 10,243 30,918 58,107 711 1,158 595 Performance Units 161,561 158,326 80,961 4,172 1,889 — Unit Awards — — — 22,846 18,895 — Total 1,456,296 1,277,480 902,911 $ 37,940 $ 30,699 $ 8,727
Restricted unit award activity	A summary of our restricted unit activity for domestic employees and, beginning January 1, 2019, NEDs is as follows: Number of Restricted Units Weighted-Average Grant-Date Fair Value Per Unit Nonvested units as of January 1, 2017 647,340 $ 39.72 Granted 307,009 29.56 Vested (201,466 ) 38.74 Forfeited (16,137 ) 40.00 Nonvested units as of December 31, 2017 736,746 35.95 Converted on July 20, 2018 53,447 24.99 Granted 518,282 24.07 Vested (235,746 ) 35.12 Forfeited (44,245 ) 36.05 Nonvested units as of December 31, 2018 1,028,484 29.47 NEDs 59,752 20.93 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
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 units is shown below: Granted for Accounting Purposes Total Performance Units Awarded Performance Units Weighted-Average Grant Date Fair Value per Unit Outstanding as of January 1, 2017 77,014 35,373 $ 31.75 Granted 39,320 38,865 50.04 Performance adjustments (a) 17,690 17,690 31.75 Vested (53,063 ) (53,063 ) 31.75 Outstanding as of December 31, 2017 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 (a) Represents the additional units issued to employees resulting from performance that exceeded the specified targets for the performance measures.
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 11, 2020 $ 22,846 822,979 563,806 February 11, 2019 $ 17,537 704,886 482,971 July 23, 2018 $ 1,358 55,133 35,745

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 2018 2017 (Thousands of Dollars) Current: U.S. $ 3,741 $ 4,515 $ 3,117 Foreign 1,489 4,658 6,335 Foreign withholding tax 101 192 479 Total current 5,331 9,365 9,931 Deferred: U.S. (490 ) 1,403 1,468 Foreign (168 ) 394 (1,065 ) Foreign withholding tax 182 246 (397 ) Total deferred (476 ) 2,043 6 Less: amounts reported in discontinued operations 101 1,251 2,164 Income tax expense $ 4,754 $ 10,157 $ 7,773
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, 2019 2018 (Thousands of Dollars) Deferred income tax assets: Net operating losses $ 26,081 $ 21,009 Employee benefits 372 362 Environmental and legal reserves 267 239 Allowance for bad debt — 1,970 Capital loss 3,870 — Other 328 1,796 Total deferred income tax assets 30,918 25,376 Less: Valuation allowance (17,743 ) (12,442 ) Net deferred income tax assets 13,175 12,934 Deferred income tax liabilities: Property, plant and equipment (25,169 ) (25,128 ) Foreign withholding tax (433 ) (234 ) Total deferred income tax liabilities (25,602 ) (25,362 ) Net deferred income tax liability $ (12,427 ) $ (12,428 ) Reported on the consolidated balance sheets as: Deferred income tax liability $ (12,427 ) $ (12,428 )

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 2018 2017 (Thousands of Dollars) Revenues: Pipeline $ 701,830 $ 611,065 $ 516,288 Storage: Third parties 453,976 443,546 438,677 Intersegment 25 42 4,339 Total storage 454,001 443,588 443,016 Fuels marketing 342,215 465,651 489,807 Consolidation and intersegment eliminations (25 ) (42 ) (4,339 ) Total revenues $ 1,498,021 $ 1,520,262 $ 1,444,772 Depreciation and amortization expense: Pipeline $ 166,991 $ 153,943 $ 128,061 Storage 97,573 93,345 91,696 Total segment depreciation and amortization expense 264,564 247,288 219,757 Other depreciation and amortization expense 8,360 8,604 8,435 Total depreciation and amortization expense $ 272,924 $ 255,892 $ 228,192 Operating income: Pipeline $ 332,480 $ 272,695 $ 231,795 Storage 154,105 155,708 172,720 Fuels marketing 20,578 15,964 1,987 Consolidation and intersegment eliminations (32 ) 32 (1 ) Total segment operating income 507,131 444,399 406,501 General and administrative expenses 107,855 100,067 107,556 Other depreciation and amortization expense 8,360 8,604 8,435 Total operating income $ 390,916 $ 335,728 $ 290,510
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, 2019 2018 2017 (Thousands of Dollars) United States $ 1,465,135 $ 1,481,844 $ 1,406,776 Foreign 32,886 38,418 37,996 Consolidated revenues $ 1,498,021 $ 1,520,262 $ 1,444,772
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, 2019 2018 (Thousands of Dollars) United States $ 4,000,647 $ 3,688,631 Foreign 118,332 86,171 Consolidated property, plant and equipment, net $ 4,118,979 $ 3,774,802
Schedule of Segment Reporting Information Assets By Segment [Text Block]	Total assets by reportable segment were as follows: December 31, 2019 2018 (Thousands of Dollars) Pipeline $ 3,884,819 $ 3,637,226 Storage 2,082,832 1,902,764 Fuels marketing 31,064 37,252 Total segment assets 5,998,715 5,577,242 Assets held for sale — 599,347 Other partnership assets 187,277 172,551 Total consolidated assets $ 6,185,992 $ 6,349,140
Schedule of Capital Expenditures, by Segment [Table Text Block]	Capital expenditures, including acquisitions, by reportable segment were as follows: Year Ended December 31, 2019 2018 2017 (Thousands of Dollars) Pipeline $ 387,702 $ 288,035 $ 1,596,311 Storage 141,972 202,782 244,398 Other partnership assets 3,894 4,137 5,648 Total capital expenditures $ 533,568 $ 494,954 $ 1,846,357

CONDENSED CONSOLIDATING FINAN_2

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
CONDENSED CONSOLIDATING FINANCIAL STATEMENTS [Abstract]
Condensed Consolidating Balance Sheets [Table Text Block]	Condensed Consolidating Balance Sheets December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Assets Cash and cash equivalents $ 176 $ 24 $ — $ 15,992 $ — $ 16,192 Receivables, net — 317 4 152,209 — 152,530 Inventories — 1,953 4,821 5,619 — 12,393 Prepaid and other current assets 61 16,325 600 4,947 — 21,933 Intercompany receivable — 1,276,839 — 610,298 (1,887,137 ) — Total current assets 237 1,295,458 5,425 789,065 (1,887,137 ) 203,048 Property, plant and equipment, net — 2,058,530 612,128 1,448,321 — 4,118,979 Intangible assets, net — 39,683 — 641,949 — 681,632 Goodwill — 149,453 170,652 685,748 — 1,005,853 Investment in wholly owned subsidiaries 2,871,540 1,743,066 1,155,855 490,826 (6,261,287 ) — Other long-term assets, net 98 111,362 32,121 32,899 — 176,480 Total assets $ 2,871,875 $ 5,397,552 $ 1,976,181 $ 4,088,808 $ (8,148,424 ) $ 6,185,992 Liabilities, Mezzanine Equity and Partners’ Equity Accounts payable $ 5,427 $ 42,064 $ 8,379 $ 53,964 $ — $ 109,834 Short-term debt and current portion of finance leases — 9,722 299 25 — 10,046 Current portion of long-term debt — 452,367 — — — 452,367 Accrued interest payable — 37,888 4 33 — 37,925 Accrued liabilities 1,425 40,514 8,461 53,885 — 104,285 Taxes other than income tax 125 7,311 5,160 185 — 12,781 Income tax payable — 492 2 3,831 — 4,325 Intercompany payable 438,857 — 1,448,280 — (1,887,137 ) — Total current liabilities 445,834 590,358 1,470,585 111,923 (1,887,137 ) 731,563 Long-term debt, less current portion — 2,871,786 1,127 62,005 — 2,934,918 Deferred income tax liability — 1,499 10 10,918 — 12,427 Other long-term liabilities — 65,577 13,774 69,588 — 148,939 Series D preferred units 581,935 — — — — 581,935 Total partners’ equity 1,844,106 1,868,332 490,685 3,834,374 (6,261,287 ) 1,776,210 Total liabilities, mezzanine equity and partners’ equity $ 2,871,875 $ 5,397,552 $ 1,976,181 $ 4,088,808 $ (8,148,424 ) $ 6,185,992 Condensed Consolidating Balance Sheets December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Assets Cash and cash equivalents $ 1,255 $ 51 $ — $ 10,223 $ — $ 11,529 Receivables, net — 2,212 — 108,205 — 110,417 Inventories — 1,741 5,237 1,456 — 8,434 Prepaid and other current assets 61 14,422 908 1,983 — 17,374 Assets held for sale — — — 599,347 — 599,347 Intercompany receivable — 1,327,833 — 500,583 (1,828,416 ) — Total current assets 1,316 1,346,259 6,145 1,221,797 (1,828,416 ) 747,101 Property, plant and equipment, net — 1,858,264 615,549 1,300,989 — 3,774,802 Intangible assets, net — 49,107 — 683,949 — 733,056 Goodwill — 149,453 170,652 685,748 — 1,005,853 Investment in wholly owned subsidiaries 3,355,636 1,750,256 1,425,283 857,485 (7,388,660 ) — Other long-term assets, net 304 54,429 26,716 6,879 — 88,328 Total assets $ 3,357,256 $ 5,207,768 $ 2,244,345 $ 4,756,847 $ (9,217,076 ) $ 6,349,140 Liabilities, Mezzanine Equity and Partners’ Equity Accounts payable $ 6,460 $ 39,680 $ 6,331 $ 50,651 $ — $ 103,122 Short-term debt — 18,500 — — — 18,500 Accrued interest payable — 36,253 — 40 — 36,293 Accrued liabilities 1,280 24,858 8,082 40,198 — 74,418 Taxes other than income tax 125 7,285 4,718 4,695 — 16,823 Income tax payable — 457 2 3,986 — 4,445 Liabilities held for sale — — — 69,834 — 69,834 Intercompany payable 472,790 — 1,355,626 — (1,828,416 ) — Total current liabilities 480,655 127,033 1,374,759 169,404 (1,828,416 ) 323,435 Long-term debt — 3,050,531 — 61,465 — 3,111,996 Deferred income tax liability — 1,675 9 10,744 — 12,428 Other long-term liabilities — 28,392 12,348 38,818 — 79,558 Series D preferred units 563,992 — — — — 563,992 Total partners’ equity 2,312,609 2,000,137 857,229 4,476,416 (7,388,660 ) 2,257,731 Total liabilities, mezzanine equity and partners’ equity $ 3,357,256 $ 5,207,768 $ 2,244,345 $ 4,756,847 $ (9,217,076 ) $ 6,349,140
Condensed Consolidating Statements of Income (Loss) [Table Text Block]	Condensed Consolidating Statements of (Loss) Income For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 545,863 $ 258,420 $ 694,485 $ (747 ) $ 1,498,021 Costs and expenses 2,574 338,291 159,376 607,611 (747 ) 1,107,105 Operating (loss) income (2,574 ) 207,572 99,044 86,874 — 390,916 Equity in earnings of subsidiaries 208,995 42,139 51,537 144,366 (447,037 ) — Interest income (expense), net 415 (187,337 ) (6,961 ) 10,813 — (183,070 ) Other income (expense), net — 3,002 744 (4 ) — 3,742 Income from continuing operations before income tax expense (benefit) 206,836 65,376 144,364 242,049 (447,037 ) 211,588 Income tax expense (benefit) 2 (230 ) 3 4,979 — 4,754 Income from continuing operations, net of tax 206,834 65,606 144,361 237,070 (447,037 ) 206,834 (Loss) income from discontinued operations, net of tax (a) (312,527 ) 7,912 (320,439 ) (640,877 ) 953,404 (312,527 ) Net (loss) income $ (105,693 ) $ 73,518 $ (176,078 ) $ (403,807 ) $ 506,367 $ (105,693 ) (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations. Condensed Consolidating Statements of Income (Loss) For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 485,603 $ 260,679 $ 774,685 $ (705 ) $ 1,520,262 Costs and expenses 2,407 317,286 163,667 701,879 (705 ) 1,184,534 Operating (loss) income (2,407 ) 168,317 97,012 72,806 — 335,728 Equity in earnings of subsidiaries 148,554 17,167 62,494 152,830 (381,045 ) — Interest income (expense), net 228 (191,835 ) (7,127 ) 14,336 — (184,398 ) Other income, net — 3,876 446 880 — 5,202 Income (loss) from continuing operations before income tax expense (benefit) 146,375 (2,475 ) 152,825 240,852 (381,045 ) 156,532 Income tax expense (benefit) — 588 (3 ) 9,572 — 10,157 Income (loss) from continuing operations, net of tax 146,375 (3,063 ) 152,828 231,280 (381,045 ) 146,375 Income from discontinued operations, net of tax (a) 59,419 — 59,419 118,838 (178,257 ) 59,419 Net income (loss) $ 205,794 $ (3,063 ) $ 212,247 $ 350,118 $ (559,302 ) $ 205,794 (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations. Condensed Consolidating Statements of Income (Loss) For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Revenues $ — $ 496,454 $ 221,125 $ 728,211 $ (1,018 ) $ 1,444,772 Costs and expenses 1,868 317,871 146,243 689,298 (1,018 ) 1,154,262 Operating (loss) income (1,868 ) 178,583 74,882 38,913 — 290,510 Equity in earnings (loss) of subsidiaries 112,706 (10,616 ) 52,336 121,631 (276,057 ) — Interest income (expense), net 57 (176,897 ) (5,587 ) 10,653 — (171,774 ) Other income (expense), net — 145 3 (216 ) — (68 ) Income (loss) from continuing operations before income tax (benefit) expense 110,895 (8,785 ) 121,634 170,981 (276,057 ) 118,668 Income tax (benefit) expense — (820 ) 2 8,591 — 7,773 Income (loss) from continuing operations, net of tax 110,895 (7,965 ) 121,632 162,390 (276,057 ) 110,895 Income from discontinued operations, net of tax (a) 37,069 — 37,069 74,138 (111,207 ) 37,069 Net income (loss) $ 147,964 $ (7,965 ) $ 158,701 $ 236,528 $ (387,264 ) $ 147,964 (a) Includes equity in earnings (loss) of subsidiaries related to discontinued operations.
Condensed Consolidating Statements of Comprehensive Income (Loss) [Table Text Block]	Condensed Consolidating Statements of Comprehensive (Loss) Income For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) income $ (105,693 ) $ 73,518 $ (176,078 ) $ (403,807 ) $ 506,367 $ (105,693 ) Other comprehensive income (loss): Foreign currency translation adjustment — — — 3,527 — 3,527 Net loss on pension and other postretirement benefit adjustments, net of tax benefit — — — (1,314 ) — (1,314 ) Net loss on cash flow hedges — (15,231 ) — — — (15,231 ) Total other comprehensive (loss) income — (15,231 ) — 2,213 — (13,018 ) Comprehensive (loss) income $ (105,693 ) $ 58,287 $ (176,078 ) $ (401,594 ) $ 506,367 $ (118,711 ) Condensed Consolidating Statements of Comprehensive Income For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 205,794 $ (3,063 ) $ 212,247 $ 350,118 $ (559,302 ) $ 205,794 Other comprehensive income: Foreign currency translation adjustment — — — 4,304 — 4,304 Net gain on pension and other postretirement benefit adjustments, net of tax expense — — — 2,334 — 2,334 Net gain on cash flow hedges — 23,411 — — — 23,411 Total other comprehensive income — 23,411 — 6,638 — 30,049 Comprehensive income $ 205,794 $ 20,348 $ 212,247 $ 356,756 $ (559,302 ) $ 235,843 Condensed Consolidating Statements of Comprehensive Income (Loss) For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 147,964 $ (7,965 ) $ 158,701 $ 236,528 $ (387,264 ) $ 147,964 Other comprehensive income (loss): Foreign currency translation adjustment — — — 17,466 — 17,466 Net loss on pension and other postretirement benefit adjustments, net of tax benefit — — — (6,170 ) — (6,170 ) Net loss on cash flow hedges — (2,046 ) — — — (2,046 ) Total other comprehensive (loss) income — (2,046 ) — 11,296 — 9,250 Comprehensive income (loss) $ 147,964 $ (10,011 ) $ 158,701 $ 247,824 $ (387,264 ) $ 157,214
Condensed Consolidating Statements of Cash Flows [Table Text Block]	Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2019 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 376,999 $ 166,005 $ 126,728 $ 409,115 $ (570,090 ) $ 508,757 Cash flows from investing activities: Capital expenditures — (257,117 ) (28,592 ) (247,859 ) — (533,568 ) Change in accounts payable related to capital expenditures — 1,369 1,212 (15,312 ) — (12,731 ) Proceeds from sale or disposition of assets — 247 90 227,815 — 228,152 Investment in subsidiaries — (11,999 ) — — 11,999 — Other, net — — — (1,100 ) — (1,100 ) Net cash used in investing activities — (267,500 ) (27,290 ) (36,456 ) 11,999 (319,247 ) Cash flows from financing activities: Debt borrowings — 1,415,580 — 42,800 — 1,458,380 Debt repayments — (1,207,000 ) — (42,400 ) — (1,249,400 ) Issuance of common units, net of issuance costs 15,000 — — — — 15,000 Distributions to preferred unitholders (121,693 ) (60,846 ) (60,847 ) (60,853 ) 182,546 (121,693 ) Distributions to common unitholders (258,354 ) (129,177 ) (129,177 ) (129,190 ) 387,544 (258,354 ) Contributions from affiliates — — — 11,999 (11,999 ) — Net intercompany activity (2,010 ) 101,980 90,734 (190,704 ) — — Other, net (11,021 ) (10,281 ) (148 ) (133 ) — (21,583 ) Net cash (used in) provided by financing activities (378,078 ) 110,256 (99,438 ) (368,481 ) 558,091 (177,650 ) Effect of foreign exchange rate changes on cash — — — (524 ) — (524 ) Net (decrease) increase in cash, cash equivalents and restricted cash (1,079 ) 8,761 — 3,654 — 11,336 Cash, cash equivalents and restricted cash as of the beginning of the period 1,255 51 — 12,338 — 13,644 Cash, cash equivalents and restricted cash as of the end of the period $ 176 $ 8,812 $ — $ 15,992 $ — $ 24,980 Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2018 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 444,233 $ 100,385 $ 179,512 $ 514,936 $ (694,859 ) $ 544,207 Cash flows from investing activities: Capital expenditures — (71,044 ) (19,152 ) (367,256 ) — (457,452 ) Change in accounts payable related to capital expenditures — 11,101 (5,161 ) (13,623 ) — (7,683 ) Acquisitions — — (37,502 ) — — (37,502 ) Proceeds from insurance recoveries — — — 78,419 — 78,419 Proceeds from sale or disposition of assets — 2,674 31 267,735 — 270,440 Investment in subsidiaries (708,600 ) (1,711,975 ) (54,600 ) (54,665 ) 2,529,840 — Net cash used in investing activities (708,600 ) (1,769,244 ) (116,384 ) (89,390 ) 2,529,840 (153,778 ) Cash flows from financing activities: Debt borrowings — 1,840,853 — 31,800 — 1,872,653 Debt repayments — (2,349,476 ) — (32,300 ) — (2,381,776 ) Issuance of Series D preferred units 590,000 — — — — 590,000 Payment of issuance costs for (34,203 ) — — — — (34,203 ) Issuance of common units, net of 10,000 — — — — 10,000 General partner contribution 204 — — — — 204 Distributions to preferred unitholders (90,670 ) (45,336 ) (45,336 ) (45,335 ) 136,007 (90,670 ) Distributions to common unitholders and general partner (300,777 ) (150,388 ) (150,388 ) (150,408 ) 451,184 (300,777 ) Cash consideration for Merger (67,936 ) — — 141 — (67,795 ) Proceeds from termination of interest rate swaps — 8,048 — — — 8,048 Contributions from affiliates — 599,400 54,600 1,768,172 (2,422,172 ) — Net intercompany activity 162,498 1,766,881 77,996 (2,007,375 ) — — Other, net (4,379 ) (1,101 ) — (71 ) — (5,551 ) Net cash provided by (used in) financing activities 264,737 1,668,881 (63,128 ) (435,376 ) (1,834,981 ) (399,867 ) Effect of foreign exchange rate changes on cash — — — (1,210 ) — (1,210 ) Net increase (decrease) in cash and cash equivalents 370 22 — (11,040 ) — (10,648 ) Cash and cash equivalents as of the beginning of the period 885 29 — 23,378 — 24,292 Cash and cash equivalents as of the end of the period $ 1,255 $ 51 $ — $ 12,338 $ — $ 13,644 Condensed Consolidating Statements of Cash Flows For the Year Ended December 31, 2017 (Thousands of Dollars) NuStar Energy NuStar Logistics NuPOP Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by operating activities $ 483,481 $ 152,101 $ 102,405 $ 405,950 $ (737,138 ) $ 406,799 Cash flows from investing activities: Capital expenditures — (47,600 ) (35,041 ) (301,997 ) — (384,638 ) Change in accounts payable related to capital expenditures — (1,988 ) 5,964 32,927 — 36,903 Acquisitions — — — (1,461,719 ) — (1,461,719 ) Proceeds from Axeon term loan — 110,000 — — — 110,000 Proceeds from insurance recoveries — — — 977 — 977 Proceeds from sale or disposition of assets — 1,955 18 63 — 2,036 Investment in subsidiaries (1,262,000 ) — — (126 ) 1,262,126 — Net cash (used in) provided by investing activities (1,262,000 ) 62,367 (29,059 ) (1,729,875 ) 1,262,126 (1,696,441 ) Cash flows from financing activities: Debt borrowings — 2,969,400 — 90,700 — 3,060,100 Debt repayments — (2,400,739 ) — (86,800 ) — (2,487,539 ) Issuance of preferred units, net of 538,560 — — — — 538,560 Issuance of common units, net of 643,878 — — — — 643,878 General partner contribution 13,737 — — — — 13,737 Distributions to preferred unitholders (38,833 ) (19,417 ) (19,416 ) (19,418 ) 58,251 (38,833 ) Distributions to common unitholders and general partner (446,306 ) (223,153 ) (223,153 ) (223,176 ) 669,482 (446,306 ) Contributions from — 1,262,000 — (9,279 ) (1,252,721 ) — Net intercompany activity 73,206 (1,801,218 ) 169,223 1,558,789 — — Other, net (5,708 ) (1,317 ) — (300 ) — (7,325 ) Net cash provided by (used in) financing activities 778,534 (214,444 ) (73,346 ) 1,310,516 (524,988 ) 1,276,272 Effect of foreign exchange rate changes on cash — — — 1,720 — 1,720 Net increase (decrease) in cash and cash equivalents 15 24 — (11,689 ) — (11,650 ) Cash and cash equivalents as of the beginning of the period 870 5 — 35,067 — 35,942 Cash and cash equivalents as of the end of the period $ 885 $ 29 $ — $ 23,378 $ — $ 24,292

QUARTERLY FINANCIAL DATA (UNA_2

QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	The following table summarizes quarterly financial data for the years ended December 31, 2019 and 2018 : First Quarter Second Quarter Third Quarter Fourth Quarter Total (Thousands of Dollars, Except Per Unit Data) 2019: Revenues $ 347,826 $ 372,445 $ 378,056 $ 399,694 $ 1,498,021 Operating income $ 73,605 $ 93,283 $ 99,972 $ 124,056 $ 390,916 Income from continuing operations, net of tax $ 28,923 $ 46,915 $ 52,588 $ 78,408 $ 206,834 Loss from discontinued operations, net of tax (306,786 ) (964 ) (4,777 ) — (312,527 ) Net (loss) income $ (277,863 ) $ 45,951 $ 47,811 $ 78,408 $ (105,693 ) Basic and diluted net (loss) income per common unit: Continuing operations $ (0.06 ) $ 0.11 $ 0.15 $ 0.40 $ 0.60 Discontinued operations (2.85 ) (0.01 ) (0.04 ) — (2.90 ) Total $ (2.91 ) $ 0.10 $ 0.11 $ 0.40 $ (2.30 ) Cash distributions per unit applicable to common limited partners $ 0.60 $ 0.60 $ 0.60 $ 0.60 $ 2.40 2018: Revenues $ 376,727 $ 389,256 $ 380,142 $ 374,137 $ 1,520,262 Operating income $ 83,493 $ 76,387 $ 89,165 $ 86,683 $ 335,728 Income from continuing operations, net of tax $ 33,233 $ 26,909 $ 43,663 $ 42,570 $ 146,375 Income (loss) from discontinued operations, net of tax 92,900 2,490 4,473 (40,444 ) 59,419 Net income $ 126,133 $ 29,399 $ 48,136 $ 2,126 $ 205,794 Basic and diluted net income (loss) per common unit: Continuing operations $ 0.18 $ 0.12 $ (3.53 ) $ 0.07 $ (3.34 ) Discontinued operations 0.97 0.03 0.04 (0.38 ) 0.57 Total $ 1.15 $ 0.15 $ (3.49 ) $ (0.31 ) $ (2.77 ) Cash distributions per unit applicable to common limited partners $ 0.60 $ 0.60 $ 0.60 $ 0.60 $ 2.40 The quarterly financial data in the table above includes the following: • impairment and goodwill losses of $297.3 million and $31.1 million , respectively, in the first quarter of 2019 (please refer to Note 5 for further discussion); • the $43.4 million non-cash loss associated with the sale of our European Operations in the fourth quarter of 2018 (please refer to Note 5 for further discussion); and • the $78.8 million gain from hurricane insurance proceeds received in the first quarter of 2018 (please refer to Note 1 for further discussion). Basic and diluted net income (loss) per common unit also includes the impact of the $377.1 million loss as a result of the Merger in 2018. Please refer to Notes 4 and 21 for further discussion.

ORGANIZATION AND OPERATIONS Nar

ORGANIZATION AND OPERATIONS Narrative 1 (Details) $ in Thousands	Oct. 15, 2019	Jul. 29, 2019USD ($)	Nov. 30, 2018USD ($)bbl	Dec. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset and goodwill impairment losses					$ 336,838	$ 0	$ 0
(Gain) loss, property damage					0	(78,756)	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
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.
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 of European operations					$ 0	$ (43,366)	$ 0
Selby, California Fire [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impact of fire at Selby, CA terminal	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

ORGANIZATION AND OPERATIONS N_2

ORGANIZATION AND OPERATIONS Narrative 2 (Details)	Jul. 20, 2018Rate
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common unit conversion rate	55.00%

ORGANIZATION AND OPERATIONS N_3

ORGANIZATION AND OPERATIONS Narrative 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unusual or Infrequent Item, or Both [Line Items]
(Gain) loss, property damage	$ 0	$ (78,756)	$ 0
Hurricane damage at St. Eustatius terminal [Member]
Unusual or Infrequent Item, or Both [Line Items]
Insurance proceeds		87,500	12,500
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	3,800
Hurricane damage at St. Eustatius terminal [Member] | (Loss) income from discontinued operations, net of tax [Member]
Unusual or Infrequent Item, or Both [Line Items]
(Gain) loss, property damage		$ (78,800)	$ 5,000

ORGANIZATION AND OPERATIONS N_4

ORGANIZATION AND OPERATIONS Narrative 4 (Details) - USD ($) $ in Thousands	Nov. 26, 2019	Jun. 29, 2018	May 04, 2017	Apr. 28, 2017	Apr. 18, 2017	Feb. 22, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 26, 2014
Class of Stock [Line Items]
Net proceeds from issuance of units							$ 15,000	$ 10,204	$ 657,475
Debt Instrument [Line Items]
Proceeds from note offering, net of issuance costs							491,580	0	543,333
Financing Receivable, Impaired [Line Items]
Proceeds from Axeon term loan							$ 0	$ 0	$ 110,000
Common Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)	527,426	413,736			14,375,000		527,426	413,736	14,375,000
Proceeds from common unit issuance including general partner contribution		$ 10,200			$ 657,500
Net proceeds from issuance of units							$ 15,000	$ 10,000	$ 643,878
Series B Preferred Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)				15,400,000
Preferred units distribution percentage				7.625%
Net proceeds from issuance of units				$ 371,800
5.625% senior notes
Debt Instrument [Line Items]
Senior notes issued				$ 550,000			$ 550,000	$ 550,000
Stated interest rate				5.625%			5.625%
Axeon [Member]
Financing Receivable, Impaired [Line Items]
Axeon Term Loan Receivable											$ 190,000
Maximum Amount Guarantees										$ 125,000
Proceeds from Axeon term loan						$ 110,000
Navigator Acquisition [Member]
Business Acquisition [Line Items]
Purchase price of Navigator Acquisition			$ 1,500,000

ORGANIZATION AND OPERATIONS N_5

ORGANIZATION AND OPERATIONS Narrative 5 (Details) bbl in Millions	12 Months Ended
	Dec. 31, 2019mibbl
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	2,155
Storage capacity, in barrels | bbl	5.2
Pipeline Segment | East and North Pipelines
Segment Information
Pipeline length, in miles	2,600
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	61.3

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Narrative (Details) - USD ($)	Oct. 01, 2018	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Goodwill impairment loss	$ 0
Asset impairment losses		$ 8,400,000	$ 297,300,000		$ 305,700,000
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 2018, 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%		2.00%
Other long-term assets, net
Restricted cash					$ 8,800,000
Other long-term liabilities
Asset retirement obligation					$ 200,000		$ 200,000

NEW ACCOUNTING PRONOUNCEMENTS N

NEW ACCOUNTING PRONOUNCEMENTS Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Leases [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Transition adjustment	The transition adjustment related to the adoption was immaterial

MERGER AND RELATED PARTY AGRE_3

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, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 20, 2018
Class of Stock [Line Items]
General partner ownership interest	2.00%				2.00%
Common unit conversion rate						55.00%
Approximate cash consideration for merger				$ 68
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	13,409,593	0

MERGER AND RELATED PARTY AGRE_4

MERGER AND RELATED PARTY AGREEMENTS Table - Merger Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 20, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ (377,079)	$ 0
Basic weighted-average common units outstanding		107,789,030	99,490,495	88,825,964
Loss per common unit attributable to the Merger			$ (3.79)

MERGER AND RELATED PARTY AGRE_5

MERGER AND RELATED PARTY AGREEMENTS Narrative 2 (Details)	12 Months Ended
	Dec. 31, 2019
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.

DISCONTINUED OPERATIONS AND I_3

DISCONTINUED OPERATIONS AND IMPAIRMENTS Narrative 1 (Details) - USD ($)	Jul. 29, 2019	Nov. 30, 2018	Oct. 01, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment losses				$ 8,400,000	$ 297,300,000	$ 305,700,000
Goodwill impairment loss			$ 0
Goodwill						1,005,853,000	$ 1,005,853,000	$ 1,008,667,000
Loss from sale of the St. Eustatius Operations						3,900,000
The European Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale		$ 270,000,000
Description of assets sold		six liquids storage terminals in the United Kingdom and one facility in Amsterdam
Loss on sale of European operations						0	(43,366,000)	0
The St. Eustatius Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale	$ 230,000,000
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.
Loss from sale of the St. Eustatius Operations						$ 3,942,000	$ 0	$ 0
St. Eustatius Bunkers [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment loss					31,100,000
Goodwill					$ 0

DISCONTINUED OPERATIONS AND I_4

DISCONTINUED OPERATIONS AND IMPAIRMENTS Table 1 - Discontinued Operations Income Statement Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations before income tax expense									$ (312,426)	$ 60,670	$ 39,233
Income tax expense									101	1,251	2,164
(Loss) income from discontinued operations, net of tax	$ 0	$ (4,777)	$ (964)	$ (306,786)	$ (40,444)	$ 4,473	$ 2,490	$ 92,900	(312,527)	59,419	37,069
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]
Revenues									248,981	441,495	369,247
Cost of revenues									220,595	407,256	318,532
Impairment losses									336,838	0	0
General and administrative expenses (excluding depreciation and amortization expense)									1,231	6,133	4,684
Other deprecation and amortization expense									0	271	263
Total costs and expenses									558,664	413,660	323,479
Operating (loss) income									(309,683)	27,835	45,768
Interest income, net									32
Interest expense, net										(1,839)	(1,309)
Other expense, net									$ (2,775)		$ (5,226)
Other income, net										$ 34,674

DISCONTINUED OPERATIONS AND I_5

DISCONTINUED OPERATIONS AND IMPAIRMENTS Table 2 - Discontinued Operations Cash Flow Disclosures (Details) - USD ($)	Oct. 01, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment losses		$ 8,400,000	$ 297,300,000	$ 305,700,000
Goodwill impairment loss	$ 0
Loss from sale of the St. Eustatius Operations				3,900,000
Gain from insurance recoveries				0	$ (78,756,000)	$ 0
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				(27,954,000)	(114,811,000)	(153,785,000)
Depreciation and amortization expense				8,536,000	41,982,000	36,040,000
Asset impairment losses				305,715,000	0	0
Goodwill impairment loss				31,123,000	0	0
Gain from insurance recoveries				0	(78,756,000)	0
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				3,942,000	0	0
The European Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale of European operations				$ 0	$ 43,366,000	$ 0

DISCONTINUED OPERATIONS AND I_6

DISCONTINUED OPERATIONS AND IMPAIRMENTS Table 3 - Reconciliation - Assets Held for Sale and Liabilities Held for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 0	$ 599,347
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]
Total current assets		54,404
Property, plant and equipment, net		513,820
Goodwill		31,123
Current liabilities		$ 69,834

ACQUISITIONS Narrative 1 (Detai

ACQUISITIONS Narrative 1 (Details) - CHS Acquisition [Member] $ in Millions	Apr. 16, 2018USD ($)
Business Acquisition [Line Items]
Description of CHS Acquisition	On April 16, 2018, we acquired CHS Inc.’s Council Bluffs pipeline system, comprised of a 227-mile pipeline and 18 storage tanks
Purchase price of CHS Acquisition	$ 37.5

ACQUISITIONS Table 1 - Navigato

ACQUISITIONS Table 1 - Navigator Acquisition Purchase Price Allocation (Details) - USD ($) $ in Thousands	May 04, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 1,005,853	$ 1,005,853	$ 1,008,667
Navigator Acquisition [Member]
Business Acquisition [Line Items]
Purchase price of Navigator Acquisition	$ 1,500,000
Accounts receivable	4,747
Other current assets	2,359
Property, plant and equipment, net	376,690
Intangible assets	700,000
Goodwill	398,024
Other long-term assets, net	2,199
Current liabilities	(22,300)
Purchase price allocation, net of cash acquired	$ 1,461,719
Intangible assets, weighted average useful life (years)	20 years

ACQUISITIONS Narrative 2 (Detai

ACQUISITIONS Narrative 2 (Details) - USD ($) $ in Thousands	Nov. 26, 2019	Jun. 29, 2018	Apr. 28, 2017	Apr. 18, 2017	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Contributions from general partner							$ 0	$ 204	$ 13,737
General partner ownership interest					2.00%				2.00%
Common Limited Partner [Member]
Business Acquisition [Line Items]
Issuance of units (units)	527,426	413,736		14,375,000			527,426	413,736	14,375,000
General Partner [Member]
Business Acquisition [Line Items]
Contributions from general partner				$ 13,600		$ 200
General partner ownership interest					2.00%
Series B Preferred Limited Partner [Member]
Business Acquisition [Line Items]
Issuance of units (units)			15,400,000
Logistics Notes Due 2027 [Member]
Business Acquisition [Line Items]
Senior notes issued			$ 550,000				$ 550,000	$ 550,000
Stated interest rate			5.625%				5.625%

ACQUISITIONS Table 2 - Navigato

ACQUISITIONS Table 2 - Navigator Pro Forma Information (Details) - Navigator Acquisition [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / shares
Business Acquisition [Line Items]
Revenues	$ 1,828,418
Net income	$ 127,433
Basic net income per common unit | $ / shares	$ 0.31
Diluted net income per common unit | $ / shares	$ 0.31
Transaction costs	$ 14,100

REVENUE FROM CONTRACTS WITH C_3

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 1 - Adoption Impact of 606 (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Operating income (loss)	124,056	99,972	93,283	73,605	86,683	89,165	76,387	83,493	390,916	335,728	290,510
Net income from continuing operations	$ 78,408	$ 52,588	$ 46,915	$ 28,923	$ 42,570	$ 43,663	$ 26,909	$ 33,233	$ 206,834	$ 146,375	$ 110,895
Basic net income (loss) per common unit from continuing operations	$ 0.40	$ 0.15	$ 0.11	$ (0.06)	$ 0.07	$ (3.53)	$ 0.12	$ 0.18	$ 0.60	$ (3.34)	$ 0.23
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Revenue Recognition [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues										$ 1,526,447
Operating income (loss)										341,913
Net income from continuing operations										$ 152,560
Basic net income (loss) per common unit from continuing operations										$ (3.27)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Revenue Recognition [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenues										$ (6,185)
Operating income (loss)										(6,185)
Net income from continuing operations										$ (6,185)
Basic net income (loss) per common unit from continuing operations										$ (0.07)

REVENUE FROM CONTRACTS WITH C_4

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

REVENUE FROM CONTRACTS WITH C_5

REVENUE FROM CONTRACTS WITH CUSTOMERS Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended		15 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Revenue recognized			$ 77,466	$ 57,826
Additions to contract liability			$ 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 C_6

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 3 - Expected Timing of Satisfaction of Performance Obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 1,884,981
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 529,830
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]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 376,500
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	$ 310,632
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	$ 236,853
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	$ 175,358
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	$ 255,808
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period

REVENUE FROM CONTRACTS WITH C_7

REVENUE FROM CONTRACTS WITH CUSTOMERS Table 4 - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues									(25)	(42)	(4,339)
Pipeline Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									693,005	611,011	516,288
Lessor revenues									8,825	54	0
Revenues									701,830	611,065	516,288
Pipeline Segment | Crude Oil Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									316,417	248,261	187,874
Pipeline Segment | Refined Products and Ammonia Pipelines [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									376,588	362,750	328,414
Storage Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									413,227	403,739	403,890
Lessor revenues									40,774	39,849	39,126
Revenues									454,001	443,588	443,016
Storage Segment | Throughput Terminal [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									114,243	83,157	85,927
Storage Segment | Storage Terminal [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									298,984	320,582	317,963
Fuels Marketing Segment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customer									$ 342,215	$ 465,651	$ 489,807

ALLOWANCE FOR DOUBTFUL ACCOUN_3

ALLOWANCE FOR DOUBTFUL ACCOUNTS Table - Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable Additional Disclosures [Abstract]
Balance as of beginning of year	$ 9,412	$ 9,380	$ 7,700
Increase in allowance, net	2,322	233	1,705
Accounts charged against the allowance	(11,662)	(201)	(25)
Balance as of end of year	$ 72	$ 9,412	$ 9,380

INVENTORIES Table - Inventories

INVENTORIES Table - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
Petroleum products	$ 8,646	$ 4,853
Materials and supplies	3,747	3,581
Total	$ 12,393	$ 8,434

PROPERTY, PLANT AND EQUIPMENT T

PROPERTY, PLANT AND EQUIPMENT Table - Property, Plant and Equipment, at Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 6,187,144	$ 5,627,805
Less accumulated depreciation and amortization	(2,068,165)	(1,853,003)
Property, plant and equipment, net	4,118,979	3,774,802
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	144,409	138,487
Land and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	223,220	181,578
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	166,878	146,517
Pipelines, storage and terminals
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	5,038,468	4,702,421
Rights-of-way
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	350,026	301,738
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 264,143	$ 157,064
Minimum [Member] | Land and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Minimum [Member] | Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	15 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 and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Maximum [Member] | Buildings
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 N

PROPERTY, PLANT AND EQUIPMENT Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Capitalized interest costs	$ 8.9	$ 7.8	$ 5.5
Depreciation and amortization expense for property, plant and equipment	$ 226	$ 243.5	$ 222.5

INTANGIBLE ASSETS Table 1 - Int

INTANGIBLE ASSETS Table 1 - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Cost	$ 866,259	$ 866,309
Accumulated Amortization	$ (184,627)	(133,253)
Customer relationships
Intangible Assets [Line Items]
Finite-Lived intangible asset, useful life	18 years
Cost	$ 863,900	863,950
Accumulated Amortization	$ (183,832)	(132,509)
Other
Intangible Assets [Line Items]
Finite-Lived intangible asset, useful life	47 years
Cost	$ 2,359	2,359
Accumulated Amortization	$ (795)	$ (744)

INTANGIBLE ASSETS Narrative (De

INTANGIBLE ASSETS Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization expense	$ 51,400	$ 51,400	$ 39,600
2020	51,000
2021	51,000
2022	51,000
2023	45,000
2024	$ 45,000

GOODWILL Table - Changes in the

GOODWILL Table - Changes in the Carrying Amount of Goodwill by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Goodwill [Roll Forward]
Navigator Acquisition purchase price allocation adjustments (Note 6)	$ (2,814)
Goodwill	1,005,853	$ 1,005,853	$ 1,008,667
Pipeline Segment
Goodwill [Roll Forward]
Navigator Acquisition purchase price allocation adjustments (Note 6)	(2,814)
Goodwill	704,231	704,231	707,045
Storage Segment
Goodwill [Roll Forward]
Navigator Acquisition purchase price allocation adjustments (Note 6)	0
Goodwill	$ 301,622	$ 301,622	$ 301,622

GOODWILL Narrative (Details)

GOODWILL Narrative (Details) - USD ($)	Nov. 30, 2018	Oct. 01, 2018	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill allocated to European Operations	$ 57,700,000
Goodwill impairment loss		$ 0
Goodwill				$ 1,005,853,000	$ 1,005,853,000	$ 1,008,667,000
Goodwill, accumulated impairment loss, continuing operations				$ 0
St. Eustatius Bunkers [Member]
Goodwill [Line Items]
Goodwill impairment loss			$ 31,100,000
Goodwill			$ 0

ACCRUED LIABILITIES Table - Acc

ACCRUED LIABILITIES Table - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities, Current [Abstract]
Employee wages and benefit costs	$ 36,704	$ 29,518
Revenue contract liabilities	21,083	21,579
Interest rate swaps	19,169	0
Operating lease liabilities	10,416	0
Other	16,913	23,321
Accrued liabilities	$ 104,285	$ 74,418

DEBT Table 1 - Short-Term Debt

DEBT Table 1 - Short-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Short-term debt	$ 10,046	$ 18,500
Short-term line of credit
Debt Instrument [Line Items]
Short-term debt	5,500	18,500
Short-term debt and current portion of finance leases
Debt Instrument [Line Items]
Current portion of finance leases (refer to Note 17)	$ 4,546	$ 0

DEBT Narrative 1 (Details)

DEBT Narrative 1 (Details) - Short-term line of credit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 35
Weighted average annual interest rate	3.60%	4.40%

DEBT Table 2 - Long-Term Debt (

DEBT Table 2 - Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	May 22, 2019	Dec. 31, 2018	Apr. 28, 2017
Debt Instrument [Line Items]
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	$ (23,301)		$ (12,744)
Total long-term debt	3,331,839		3,111,996
Less current portion	452,367		0
Long-term debt, less current portion	2,934,918		3,111,996
Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term debt	475,000		745,000
4.80% senior notes
Debt Instrument [Line Items]
Long-term debt	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
6.00% senior notes
Debt Instrument [Line Items]
Long-term debt	500,000	$ 500,000	0
5.625% senior notes
Debt Instrument [Line Items]
Long-term debt	550,000		550,000	$ 550,000
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	365,440		365,440
Receivables Financing Agreement
Debt Instrument [Line Items]
Long-term debt	62,200		61,800
Long-term debt, less current portion
Debt Instrument [Line Items]
Finance leases (refer to Note 17)	$ 55,446		$ 0

DEBT Table 3 - Long-Term Debt R

DEBT Table 3 - Long-Term Debt Repayments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Long-term Debt, Fiscal Year Maturity [Abstract]
2020	$ 450,000
2021	837,200
2022	250,000
2023	0
2024	0
Thereafter	1,817,940
Total repayments	3,355,140
Net fair value adjustments, unamortized discounts and unamortized debt issuance costs	(23,301)	$ (12,744)
Total long-term debt	$ 3,331,839	$ 3,111,996

DEBT Narrative 2 (Details)

DEBT Narrative 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019
Debt Instrument [Line Items]
Interest payments	$ 183,800	$ 190,900	$ 163,600
Amortization of debt issuance costs and debt discount	6,500	7,100	$ 5,000
Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,200,000			$ 1,400,000
Line of credit facility, covenant terms	For the rolling period ending December 31, 2019, 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 maximum consolidated debt coverage ratio and minimum consolidated interest coverage ratio requirements may limit the amount we can borrow under the Revolving Credit Agreement to an amount less than the total amount available for borrowing. 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	$ 721,000
Letters of credit issued	4,000
Maximum letters of credit allowed	$ 400,000
Interest rate at period end	3.90%
Long-term debt	$ 475,000	$ 745,000
Interest rate during period	4.40%

DEBT Narrative 3 (Details)

DEBT Narrative 3 (Details) - USD ($)	May 22, 2019	Jan. 15, 2018	Apr. 28, 2017	Dec. 31, 2019	Dec. 31, 2018	Mar. 04, 2020	Apr. 15, 2018	Jan. 14, 2018
6.00% senior notes
Debt Instrument [Line Items]
Long-term debt	$ 500,000,000			$ 500,000,000	$ 0
Stated interest rate				6.00%
Proceeds from debt, net of issuance costs	$ 491,600,000
Debt instrument, redemption, description				If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 6.0% senior notes or the 5.625% senior notes, each holder of the 6.75% senior notes, the 6.0% senior notes or the 5.625% 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.
5.625% senior notes
Debt Instrument [Line Items]
Long-term debt			$ 550,000,000	$ 550,000,000	550,000,000
Stated interest rate			5.625%	5.625%
Proceeds from debt, net of issuance costs			$ 543,300,000
Debt instrument, redemption, description				If we undergo a change of control, as defined in the supplemental indentures for the 6.75% senior notes, the 6.0% senior notes or the 5.625% senior notes, each holder of the 6.75% senior notes, the 6.0% senior notes or the 5.625% 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				$ 450,000,000	450,000,000
Stated interest rate				4.80%
6.75% senior notes
Debt Instrument [Line Items]
Long-term debt				$ 300,000,000	300,000,000
Stated interest 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 6.0% senior notes or the 5.625% senior notes, each holder of the 6.75% senior notes, the 6.0% senior notes or the 5.625% 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.
4.75% senior notes
Debt Instrument [Line Items]
Long-term debt				$ 250,000,000	250,000,000
Stated interest rate				4.75%
7.65% senior notes
Debt Instrument [Line Items]
Long-term debt							$ 350,000,000
Stated interest rate							7.65%
Subordinated Notes
Debt Instrument [Line Items]
Long-term debt				$ 402,500,000	402,500,000
Stated interest rate				8.70%				7.625%
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%
Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Long-term debt				$ 365,440,000	365,440,000
Debt instrument, redemption, description				At the option of NuStar Logistics, during any period when the bonds bear interest at a daily or weekly rate, the GoZone Bonds may be redeemed in whole or in part on any interest payment date for 100% of the outstanding principal amount plus accrued interest to the redemption date.
Amount received from trustee				$ 0	$ 0
Amount remaining in trust				$ 43,232,000
Subsequent Event [Member] | Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Amount remaining in trust						$ 43,300,000

DEBT Table 4 - GoZone Bonds (De

DEBT Table 4 - GoZone Bonds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Go Zone Bonds Due June 2038
Debt Instrument [Line Items]
Date Issued	Jun. 26, 2008
Maturity date	Jun. 1, 2038
Long-term debt	$ 55,440
Amount of letter of credit	56,169
Amount received from trustee	55,440
Amount remaining in trust	$ 0
Weighted average annual interest rate	1.60%
Go Zone Bonds Due July 2040
Debt Instrument [Line Items]
Date Issued	Jul. 15, 2010
Maturity date	Jul. 1, 2040
Long-term debt	$ 100,000
Amount of letter of credit	101,315
Amount received from trustee	100,000
Amount remaining in trust	$ 0
Weighted average annual interest rate	1.50%
Go Zone Bonds Due October 2040
Debt Instrument [Line Items]
Date Issued	Oct. 7, 2010
Maturity date	Oct. 1, 2040
Long-term debt	$ 50,000
Amount of letter of credit	50,658
Amount received from trustee	43,741
Amount remaining in trust	$ 6,652
Weighted average annual interest rate	1.50%
Go Zone Bonds Due December 2040
Debt Instrument [Line Items]
Date Issued	Dec. 29, 2010
Maturity date	Dec. 1, 2040
Long-term debt	$ 85,000
Amount of letter of credit	86,118
Amount received from trustee	49,782
Amount remaining in trust	$ 36,580
Weighted average annual interest rate	1.50%
Go Zone Bonds Due August 2041
Debt Instrument [Line Items]
Date Issued	Aug. 9, 2011
Maturity date	Aug. 1, 2041
Long-term debt	$ 75,000
Amount of letter of credit	75,986
Amount received from trustee	75,000
Amount remaining in trust	$ 0
Weighted average annual interest rate	1.60%
Total Gulf Opportunity Zone revenue bonds
Debt Instrument [Line Items]
Long-term debt	$ 365,440	$ 365,440
Amount of letter of credit	370,246
Amount received from trustee	323,963
Amount remaining in trust	$ 43,232
Debt, weighted average interest rate	1.50%

DEBT Narrative 4 (Details)

DEBT Narrative 4 (Details) - Receivables Financing Agreement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 125
Line of credit facility, borrowing capacity, description	The amount available for borrowing is limited to $125.0 million and is based on the availability of eligible receivables and other customary factors and conditions.
Debt instrument, collateral amount	$ 112.8	$ 95.5
Weighted average annual interest rate	3.20%

HEALTH, SAFETY AND ENVIRONMEN_3

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, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance as of the beginning of year	$ 7,753	$ 5,095
Additions to accrual	3,700	5,708
Payments	(3,515)	(3,050)
Balance as of the end of year	$ 7,938	$ 7,753

HEALTH, SAFETY AND ENVIRONMEN_4

HEALTH, SAFETY AND ENVIRONMENTAL MATTERS Table 2 - Accruals for Environmental Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accrual for Environmental Loss Contingencies, Balance Sheet Classification [Abstract]
Accrued liabilities	$ 4,837	$ 4,349
Other long-term liabilities	3,101	3,404
Accruals for environmental matters	$ 7,938	$ 7,753	$ 5,095

COMMITMENTS AND CONTINGENCIES N

COMMITMENTS AND CONTINGENCIES Narrative 1 (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Loss contingency accrual, at carrying value	$ 3.7	$ 2.8

COMMITMENTS AND CONTINGENCIES T

COMMITMENTS AND CONTINGENCIES Table - Commitments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
2020	$ 8,935
2021	7,643
2022	6,202
2023	1,485
2024	812
Thereafter	5,157
Total	$ 30,234

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES Narrative 2 - Commitments (Details)	12 Months Ended
	Dec. 31, 2019
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.

LEASE ASSETS AND LIABILITIES Na

LEASE ASSETS AND LIABILITIES Narrative 1 (Details) $ in Millions	Jan. 01, 2019USD ($)
Leases [Abstract]
Right-of-Use Assets Recognized at Transition	$ 207
Lease Liabilities Recognized at Transition	$ 192

LEASE ASSETS AND LIABILITIES _2

LEASE ASSETS AND LIABILITIES Narrative 2 (Details)	12 Months Ended
	Dec. 31, 2019
Operating Lease Type [Line Items]
Lessee, operating lease, renewal term	20 years
Lessee, Finance Lease, Description [Abstract]
Lessee, finance lease, remaining term	1 year
Number of renewal periods	4
Lessee, finance lease, renewal term	5 years
Maximum [Member]
Operating Lease Type [Line Items]
Lessee, operating lease, remaining term	6 years

LEASE ASSETS AND LIABILITIES Ta

LEASE ASSETS AND LIABILITIES Table 1 (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Right-of-Use Assets:
Accumulated amortization on finance right-of-use asset	$ 3,748
Lease Liabilities:
Operating lease, current	10,416	$ 0
Total operating lease liabilities	80,499
Total finance lease liabilities	59,992
Other long-term assets, net
Right-of-Use Assets:
Operating lease	81,219
Property, plant and equipment, net of accumulated amortization of $3,748
Right-of-Use Assets:
Finance lease	74,953
Accrued liabilities
Lease Liabilities:
Operating lease, current	10,416
Other long-term liabilities
Lease Liabilities:
Operating lease, noncurrent	70,083
Short-term debt and current portion of finance leases
Lease Liabilities:
Finance lease, current	4,546	0
Long-term debt, less current portion
Lease Liabilities:
Finance lease, noncurrent	$ 55,446	$ 0

LEASE ASSETS AND LIABILITIES _3

LEASE ASSETS AND LIABILITIES Table 2 (Details) $ in Thousands	Dec. 31, 2019USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	$ 12,647
2021	9,419
2022	8,717
2023	7,605
2024	6,739
Thereafter	60,354
Total lease payments	105,481
Less: Interest	24,982
Present value of lease liabilities	80,499
Finance Lease, Liability, Payment, Due [Abstract]
2020	6,702
2021	5,252
2022	4,582
2023	4,480
2024	4,067
Thereafter	59,681
Total lease payments	84,764
Less: Interest	24,772
Present value of lease liabilities	$ 59,992

LEASE ASSETS AND LIABILITIES _4

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

LEASE ASSETS AND LIABILITIES _5

LEASE ASSETS AND LIABILITIES Narrative 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating Leases, Rent Expense, Net	$ 42.9	$ 36.2

LEASE ASSETS AND LIABILITIES _6

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

LEASE ASSETS AND LIABILITIES _7

LEASE ASSETS AND LIABILITIES Narrative 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Lessor, Lease, Description [Line Items]
Lessor, operating lease, term of contract	10 years
Lessor, operating lease, payments to be received	$ 273,700
Lease storage assets, cost	6,187,144	$ 5,627,805
Lease storage assets, accumulated depreciation	$ 2,068,165	$ 1,853,003
Assets leased to others [Member]
Lessor, Lease, Description [Line Items]
Lease storage assets, estimated useful life	30 years
Lease storage assets, cost	$ 238,200
Lease storage assets, accumulated depreciation	121,500
Service revenues [Member]
Lessor, Lease, Description [Line Items]
Operating lease, lease income	$ 40,800

DERIVATIVES AND FAIR VALUE ME_3

DERIVATIVES AND FAIR VALUE MEASUREMENTS Narrative (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Apr. 15, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Cash received from termination of interest rate swaps	$ 8,000,000
Interest rate swaps | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swaps interest rate received		receive a rate based on the three-month USD LIBOR
Notional amount of forward-starting interest rate swaps that terminate in September 2020		$ 250,000,000	$ 250,000,000
Notional amount of forward-starting interest rate swaps terminated	$ 350,000,000
7.65% senior notes
Derivative Instruments, Gain (Loss) [Line Items]
Stated interest rate				7.65%

DERIVATIVES AND FAIR VALUE ME_4

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 1 - Fair Value of Unwound Interest Rate Swap Agreements (Details) - Interest rate swaps - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current Portion of Long-Term Debt [Member]
Derivatives, Fair Value
Fair market value of unwound fixed-to-floating interest rate swaps	$ 2,755	$ 0
Long-Term Debt, Less Current Portion [Member]
Derivatives, Fair Value
Fair market value of unwound fixed-to-floating interest rate swaps	2,568	10,475
Accumulated Other Comprehensive Income (Loss) [Member]
Derivatives, Fair Value
Fair market value of unwound forward starting interest rate swaps	$ 3,045	$ (770)

DERIVATIVES AND FAIR VALUE ME_5

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 2 - Fair Values of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value
Liability Derivatives	$ (19,169)	$ 0
Level 2 [Member] | Interest rate swaps | Designated as Hedging Instrument [Member] | Other long-term assets, net
Derivatives, Fair Value
Asset Derivatives	0	627
Level 2 [Member] | Interest rate swaps | Designated as Hedging Instrument [Member] | Accrued liabilities
Derivatives, Fair Value
Liability Derivatives	(19,169)	0
Level 2 [Member] | Interest rate swaps | Designated as Hedging Instrument [Member] | Other long-term liabilities
Derivatives, Fair Value
Liability Derivatives	$ 0	$ (751)

DERIVATIVES AND FAIR VALUE ME_6

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 3 - Impact of Derivatives on Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to be reclassified during next 12 months, forward-starting interest rate swaps	$ (2,400)
Interest rate swaps | Other comprehensive income | Designated as Hedging Instrument [Member] | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss) on derivative	(19,045)	$ 17,912	$ (8,670)
Interest rate swaps | Interest expense, net | Designated as Hedging Instrument [Member] | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from AOCI into interest expense, net	$ (3,814)	$ (5,499)	$ (6,624)

DERIVATIVES AND FAIR VALUE ME_7

DERIVATIVES AND FAIR VALUE MEASUREMENTS Table 4 (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value, long-term debt	$ 3,442,001	$ 3,056,704
Long-term debt, including current portion and excluding finance leases	$ 3,331,839	$ 3,111,996

SERIES D CUMULATIVE CONVERTIB_2

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 1 (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 13, 2018	Jun. 29, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Proceeds from issuance of Series D preferred units				$ 0	$ 590,000	$ 0
Series D preferred units outstanding				23,246,650	23,246,650
Net proceeds from issuance of Series D preferred units					$ 555,797
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 CONVERTIB_3

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, 2020	Dec. 31, 2019
Class of Stock [Line Items]
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
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
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
Preferred Stock, Distributions, Period - June 29, 2023 and thereafter [Member]
Class of Stock [Line Items]
Preferred stock, dividend rate, amount per annum		$ 81.1
Preferred unit, distribution payment rate, variable description		the greater of 13.75% per annum ($81.1 million per annum) or the distribution per common unit thereafter
Preferred Stock Distributions, Period - June 16, 2019 and thereafter [Member]
Class of Stock [Line Items]
Required amount of per unit cash dividends to permit dividend paid in kind		$ 0.635
Minimum [Member] | Preferred Stock, Distributions, Period - June 29, 2023 and thereafter [Member]
Class of Stock [Line Items]
Preferred units distribution percentage		13.75%
Subsequent Event [Member]
Class of Stock [Line Items]
Cash distributions per unit applicable to limited partners	$ 0.619

SERIES D CUMULATIVE CONVERTIB_4

SERIES D CUMULATIVE CONVERTIBLE PREFERRED UNITS Narrative 3 (Details) - Series D Preferred Limited Partner [Member] $ in Millions	Jul. 20, 2018	Dec. 31, 2019USD ($)
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.
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		At any time 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).
Minimum conversion amount		$ 50
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
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 (D

PARTNERS' EQUITY Narrative 1 (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017Rate
Partners' Capital Notes [Abstract]
General partner ownership interest	2.00%	2.00%

PARTNERS' EQUITY Table 1 - Pref

PARTNERS' EQUITY Table 1 - Preferred Units (Details) - USD ($)	Nov. 30, 2017	Apr. 28, 2017	Nov. 25, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Net proceeds from issuance of units				$ 15,000,000	$ 10,204,000	$ 657,475,000
Series A Preferred Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)			9,060,000
Units issued, price per unit			$ 25
Net proceeds from issuance of units			$ 218,400,000
Preferred units liquidation preference			$ 25
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
Net proceeds from issuance of units		$ 371,800,000
Preferred units liquidation preference		$ 25
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, the 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
Net proceeds from issuance of units	$ 166,700,000
Preferred units liquidation preference	$ 25
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, the 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 (D

PARTNERS' EQUITY Narrative 2 (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 26, 2019	Jun. 29, 2018	Apr. 18, 2017	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Proceeds from issuance of common units, net of issuance costs	$ 15,000					$ 15,000	$ 10,000	$ 643,878
Contributions from general partner						$ 0	$ 204	$ 13,737
General partner ownership interest				2.00%				2.00%
Common Limited Partner [Member]
Class of Stock [Line Items]
Issuance of units (units)	527,426	413,736	14,375,000			527,426	413,736	14,375,000
Units issued, price per unit	$ 28.44	$ 24.17	$ 46.35
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued					13,400,000	0	13,409,593	0
Proceeds from common unit issuance including general partner contribution		$ 10,200	$ 657,500
Unit-based compensation (units)						775,224	225,144	185,455
General Partner [Member]
Class of Stock [Line Items]
Contributions from general partner			$ 13,600		$ 200
General partner ownership interest				2.00%

PARTNERS' EQUITY Table 2 - Bala

PARTNERS' EQUITY Table 2 - Balance of and Changes in Common Units Outstanding (Details) - shares	Nov. 26, 2019	Jun. 29, 2018	Apr. 18, 2017	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Limited partners common units outstanding (in units)					108,527,806	107,225,156
Common Limited Partner [Member]
Class of Stock [Line Items]
Limited partners common units outstanding (in units)					108,527,806	107,225,156	93,176,683	78,616,228
Issuance of units (units)	527,426	413,736	14,375,000		527,426	413,736	14,375,000
Unit-based compensation (units)					775,224	225,144	185,455
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued				13,400,000	0	13,409,593	0

PARTNERS' EQUITY Narrative 3 (D

PARTNERS' EQUITY Narrative 3 (Details)	12 Months Ended
	Dec. 31, 2019
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 - Gene

PARTNERS' EQUITY Table 3 - General Partner Incentive Distributions (Details)	6 Months Ended
	Jun. 30, 2018
Common Limited Partner [Member] | Quarterly Distributions Level 1 [Member]
Distribution Allocation [Line Items]
Quarterly distribution amount per common unit	Up to $0.60
Percentage of distribution allocated to common unitholders	98.00%
Common Limited Partner [Member] | Quarterly Distributions Level 2 [Member]
Distribution Allocation [Line Items]
Quarterly distribution amount per common unit	Above $0.60 up to $0.66
Percentage of distribution allocated to common unitholders	90.00%
Common Limited Partner [Member] | Quarterly Distributions Level 3 [Member]
Distribution Allocation [Line Items]
Quarterly distribution amount per common unit	Above $0.66
Percentage of distribution allocated to common unitholders	75.00%
General Partner [Member] | Quarterly Distributions Level 1 [Member]
Distribution Allocation [Line Items]
Percentage of distribution allocated to the general partner	2.00%
General Partner [Member] | Quarterly Distributions Level 2 [Member]
Distribution Allocation [Line Items]
Percentage of distribution allocated to the general partner	10.00%
General Partner [Member] | Quarterly Distributions Level 3 [Member]
Distribution Allocation [Line Items]
Percentage of distribution allocated to the general partner	25.00%

PARTNERS' EQUITY Table 4 - Cas

PARTNERS' EQUITY Table 4 - Cash Distributions Earned - General and Common Limited Partners (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distributions Made to Limited Partners and General Partner [Line Items]
Cash distributions to partners
General partner interest										$ 0	1,141	$ 9,252
General partner incentive distribution										0	0	45,669
Total general partner distributions										0	1,141	54,921
Common limited partners' distribution										259,136	248,705	407,681
Total cash distributions applicable to common unitbolders and general partner (distribution earned)										259,136	249,846	462,602
Common Limited Partner [Member]
Distributions Made to Limited Partners and General Partner [Line Items]
Cash distributions to partners										$ 258,354	$ 286,398	$ 391,737
Cash distributions per unit applicable to limited partners	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60		$ 2.40	$ 2.40	$ 4.38
General Partner [Member]
Distributions Made to Limited Partners and General Partner [Line Items]
Cash distributions to partners									$ 0		$ 14,379	$ 54,569

PARTNERS' EQUITY Table 5 - Cash

PARTNERS' EQUITY Table 5 - Cash Distributions Declared - General Partner and Common Limited Partners (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distribution Made to Limited Partner [Line Items]
Cash distributions applicable to common unitholders (distribution earned)	$ 65,128	$ 64,660	$ 64,658	$ 64,690
Common Limited Partner [Member]
Distribution Made to Limited Partner [Line Items]
Cash distributions per unit applicable to limited partners	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 2.40	$ 2.40	$ 4.38
Distribution date of record (distribution earned)	Feb. 10, 2020	Nov. 8, 2019	Aug. 7, 2019	May 8, 2019
Distribution payment date	Feb. 14, 2020	Nov. 14, 2019	Aug. 13, 2019	May 14, 2019

PARTNERS' EQUITY Table 6 - Net

PARTNERS' EQUITY Table 6 - Net Income Applicable to the General Partner (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income Allocation [Abstract]
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133		$ (105,693)	$ 205,794	$ 147,964
Less preferred limited partner interest										121,693	92,540	40,448
Less general partner incentive distribution										0	0	45,669
Net income (loss) after general partner incentive distribution and preferred limited partner interest												$ 61,847
General partner interest									2.00%			2.00%
General partner allocation of net income (loss)												$ 1,237
General partner incentive distribution										$ 0	0	45,669
Net income applicable to general partner											$ 2,500	$ 46,906

PARTNERS' EQUITY Table 7 - Accu

PARTNERS' EQUITY Table 7 - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (54,878)
Other comprehensive income (loss)	(13,018)	$ 30,049	$ 9,250
Ending balance	(67,896)	(54,878)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(47,299)	(51,603)	(69,069)
Other comprehensive income (loss) before reclassifications	3,527	(13,880)	17,466
Other		60
Other comprehensive income (loss)	3,527	4,304	17,466
Ending balance	(43,772)	(47,299)	(51,603)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(893)	(24,304)	(22,258)
Other comprehensive income (loss) before reclassifications	(19,045)	17,912	(8,670)
Other		0
Other comprehensive income (loss)	(15,231)	23,411	(2,046)
Ending balance	(16,124)	(893)	(24,304)
Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(6,686)	(9,020)	(2,850)
Other comprehensive income (loss) before reclassifications	1,000	3,282	(4,641)
Other		(134)
Other comprehensive income (loss)	(1,314)	2,334	(6,170)
Ending balance	(8,000)	(6,686)	(9,020)
Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(54,878)	(84,927)	(94,177)
Other comprehensive income (loss) before reclassifications	(14,518)	7,314	4,155
Other		(74)
Other comprehensive income (loss)	(13,018)	30,049	9,250
Ending balance	(67,896)	(54,878)	(84,927)
Operating expense [Member] | Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			0
Operating expense [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			0
Operating expense [Member] | Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			(1,143)
Operating expense [Member] | Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			(1,143)
General and administrative expense [Member] | Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			0
General and administrative expense [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			0
General and administrative expense [Member] | Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			(386)
General and administrative expense [Member] | Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI			(386)
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	3,814	5,499	6,624
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	3,814	5,499	$ 6,624
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
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
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	(2,314)	(814)
Pension Plan [Member] | Other Income [Member] | Total [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI	$ (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] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI		0
Sale of U.K. and Amsterdam Operations [Member] | Other Income [Member] | Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net loss (gain) reclassified from AOCI		0
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 _3

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, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Series D Preferred Unit accretion (refer to Note 19)									$ (18,085)	$ (8,195)
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133	(105,693)	205,794	$ 147,964
Distributions to preferred limited partners									(121,693)	(92,540)	(40,448)
Distributions to general partner (including incentive distribution rights)									0	(1,141)	(54,921)
Distributions to common limited partners									(259,136)	(248,705)	(407,681)
Distribution equivalent rights to restricted units									(2,659)	(2,045)	(2,965)
Distributions in excess of (loss) income									(489,181)	(138,637)	(358,051)
Distributions to common limited partners									259,136	248,705	407,681
Allocation of distributions in excess of (loss) income									(489,181)	(138,659)	(350,890)
Loss to common unitholders attributable to the Merger (refer to Note 4)									0	(377,079)	0
Net (loss) income attributable to common units									$ (248,130)	$ (275,228)	$ 56,791
Basic weighted-average common units outstanding									107,789,030	99,490,495	88,825,964
Diluted common units outstanding:
Basic weighted-average common units outstanding									107,789,030	99,490,495	88,825,964
Effect of dilutive potential common units									65,669	40,677	0
Diluted weighted-average common units outstanding									107,854,699	99,531,172	88,825,964
Basic net (loss) income per common unit	$ 0.40	$ 0.11	$ 0.10	$ (2.91)	$ (0.31)	$ (3.49)	$ 0.15	$ 1.15	$ (2.30)	$ (2.77)	$ 0.64
Diluted net income (loss) per common unit	$ 0.40	$ 0.11	$ 0.10	$ (2.91)	$ (0.31)	$ (3.49)	$ 0.15	$ 1.15	$ (2.30)	$ (2.77)	$ 0.64
Common Limited Partner [Member]
Series D Preferred Unit accretion (refer to Note 19)									$ (18,085)	$ (8,195)	$ 0
Net income (loss)									$ (227,386)	$ 110,788	$ 60,610

STATEMENTS OF CASH FLOWS Table

STATEMENTS OF CASH FLOWS Table 1 - Changes in Current Assets and Current Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Decrease (increase) in current assets:
Accounts receivable	$ (23,480)	$ 22,482	$ (865)
Receivable from related parties	0	160	112
Inventories	(866)	3,819	11,936
Prepaid and other current assets	(5,103)	3,694	3,393
Increase (decrease) in current liabilities:
Accounts payable	8,068	8,003	(30,409)
Accrued interest payable	1,632	(4,279)	6,489
Accrued liabilities	(19,614)	39,577	(11,157)
Taxes other than income tax	(5,276)	4,521	(3,529)
Income tax payable	(126)	285	(2,463)
Changes in current assets and current liabilities	$ (44,765)	$ 78,262	$ (26,493)

STATEMENTS OF CASH FLOWS Tabl_2

STATEMENTS OF CASH FLOWS Table 2 - Cash Flows Related to Interest and Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amount capitalized	$ 176,859	$ 183,078	$ 158,089
Cash paid for income taxes, net of tax refunds received	$ 6,817	$ 8,535	$ 11,338

STATEMENTS OF CASH FLOWS Tabl_3

STATEMENTS OF CASH FLOWS Table 3 - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 16,192	$ 11,529
Cash, cash equivalents and restricted cash and Restricted Cash Equivalents	24,980	13,644	$ 24,292	$ 35,942
Cash and Cash Equivalents [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	16,192	11,529
Other long-term assets, net
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, cash equivalents and restricted cash and Restricted Cash Equivalents	8,788	0
Assets Held for Sale [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, cash equivalents and restricted cash and Restricted Cash Equivalents	$ 0	$ 2,115

EMPLOYEE BENEFIT PLANS Narrativ

EMPLOYEE BENEFIT PLANS Narrative 1 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ 7.6	$ 7.4	$ 6.9
Benefit plan costs, international employees	$ 0.9	$ 2.5	$ 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

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, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for the Pension Plans				$ 164,200	$ 139,700
Change in benefit obligation:
Benefit obligation, January 1	$ 141,833	$ 149,817
Service cost	9,549	9,621	$ 8,955
Interest cost	5,480	4,824	4,507
Benefits paid	(7,109)	(7,929)
Participant contributions	0	0
Actuarial loss (gain)	17,504	(14,500)
Benefit obligation, December 31	167,257	141,833	149,817
Change in plan assets:
Plan assets at fair value, January 1	126,949	129,878
Actual return on plan assets	28,064	(6,034)
Employer contributions	11,132	11,034
Benefits paid	(7,109)	(7,929)
Participant contributions	0	0
Plan assets at fair value, December 31	159,036	126,949	129,878
Reconciliation of funded status:
Fair value of plan assets at December 31	159,036	126,949	129,878	159,036	126,949
Less: Benefit obligation at December 31	167,257	141,833	149,817	167,257	141,833
Funded status at December 31				(8,221)	(14,884)
Amounts recognized in the consolidated balance sheets:
Accrued liabilities				(303)	(267)
Other long-term liabilities				(7,918)	(14,617)
Net pension liability				(8,221)	(14,884)
Other Postretirement Benefit Plans [Member]
Change in benefit obligation:
Benefit obligation, January 1	10,908	12,410
Service cost	431	504	456
Interest cost	453	429	430
Benefits paid	(217)	(255)
Participant contributions	62	87
Actuarial loss (gain)	1,559	(2,267)
Benefit obligation, December 31	13,196	10,908	12,410
Change in plan assets:
Plan assets at fair value, January 1	0	0
Actual return on plan assets	0	0
Employer contributions	155	168
Benefits paid	(217)	(255)
Participant contributions	62	87
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	$ 13,196	$ 10,908	$ 12,410	13,196	10,908
Funded status at December 31				(13,196)	(10,908)
Amounts recognized in the consolidated balance sheets:
Accrued liabilities				(368)	(362)
Other long-term liabilities				(12,828)	(10,546)
Net pension liability				$ (13,196)	$ (10,908)

EMPLOYEE BENEFIT PLANS Table 2

EMPLOYEE BENEFIT PLANS Table 2 - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ 9,549	$ 9,621	$ 8,955
Interest cost	5,480	4,824	4,507
Expected return on plan assets	(8,015)	(7,417)	(6,411)
Amortization of prior service credit	(2,057)	(2,057)	(2,059)
Amortization of net actuarial loss	846	2,174	1,484
Net periodic benefit cost (income)	5,803	7,145	6,476
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	431	504	456
Interest cost	453	429	430
Expected return on plan assets	0	0	0
Amortization of prior service credit	(1,145)	(1,145)	(1,145)
Amortization of net actuarial loss	42	214	191
Net periodic benefit cost (income)	$ (219)	$ 2	$ (68)

EMPLOYEE BENEFIT PLANS Table 3

EMPLOYEE BENEFIT PLANS Table 3 - Adjustments to Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Income tax (expense) benefit	$ 14	$ (94)	$ 184
Total changes in other comprehensive income (loss)	(1,314)	2,334	(6,170)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	2,545	1,049	(4,235)
Amortization of prior service credit	(2,057)	(2,057)	(2,059)
Amortization of net actuarial loss	846	2,174	1,484
Net (gain) loss reclassified into income	(1,211)	117	(575)
Reclassification of stranded tax effects	0	(74)	0
Income tax (expense) benefit	14	(69)	162
Total changes in other comprehensive income (loss)	1,348	1,023	(4,648)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	(1,559)	2,267	(590)
Amortization of prior service credit	(1,145)	(1,145)	(1,145)
Amortization of net actuarial loss	42	214	191
Net (gain) loss reclassified into income	(1,103)	(931)	(954)
Reclassification of stranded tax effects	0	0	0
Income tax (expense) benefit	0	(25)	22
Total changes in other comprehensive income (loss)	$ (2,662)	$ 1,311	$ (1,522)

EMPLOYEE BENEFIT PLANS Table 4

EMPLOYEE BENEFIT PLANS Table 4 - Amounts Recorded as a Component of Accumulated Other Comprehensive (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	$ (24,564)	$ (27,955)
Prior service credit	12,490	14,547
Deferred tax asset (liability)	90	76
Accumulated other comprehensive income (loss), net of tax	(11,984)	(13,332)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	(3,190)	(1,673)
Prior service credit	7,174	8,319
Deferred tax asset (liability)	0	0
Accumulated other comprehensive income (loss), net of tax	$ 3,984	$ 6,646

EMPLOYEE BENEFIT PLANS Table 5

EMPLOYEE BENEFIT PLANS Table 5 - Amounts Expected to be Recognized in Net Periodic Benefit Cost (Income) in Following Year (Details) $ in Thousands	Dec. 31, 2019USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	$ 1,845
Prior service credit	(2,057)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	137
Prior service credit	$ (1,145)

EMPLOYEE BENEFIT PLANS Narrat_2

EMPLOYEE BENEFIT PLANS Narrative 2 (Details)	Dec. 31, 2019
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 6

EMPLOYEE BENEFIT PLANS Table 6 - Major Classes of Plan Assets Measured at Fair Value (Details) - Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 159,036	$ 126,949	$ 129,878
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	66,299	56,424
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92,737	70,525
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	160	608
Cash equivalent securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	160	608
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	92,737	70,525
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	92,737	70,525
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	17,473	13,391
International stock index fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,473	13,391
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	48,666	42,425
Bond market index fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48,666	42,425
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 Narrat_3

EMPLOYEE BENEFIT PLANS Narrative 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan contributions	$ 11,132	$ 11,034
Estimated future employer contributions in next fiscal year	11,300
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan contributions	155	$ 168
Estimated future employer contributions in next fiscal year	$ 400

EMPLOYEE BENEFIT PLANS Table 7

EMPLOYEE BENEFIT PLANS Table 7 - Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Pension Plan [Member]
Estimated Future Benefit Payments
2020	$ 9,058
2021	9,859
2022	9,987
2023	10,461
2024	10,825
Years 2025-2029	59,680
Other Postretirement Benefit Plans [Member]
Estimated Future Benefit Payments
2020	368
2021	393
2022	428
2023	481
2024	507
Years 2025-2029	$ 3,232

EMPLOYEE BENEFIT PLANS Table 8

EMPLOYEE BENEFIT PLANS Table 8 - Assumptions - Benefit Obligations (Details)	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.34%	4.40%
Rate of compensation increase	3.51%	3.51%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.43%	4.53%

EMPLOYEE BENEFIT PLANS Table 9

EMPLOYEE BENEFIT PLANS Table 9 - Assumptions - Net Periodic Benefit Cost (Income) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.40%	3.72%	4.33%
Expected long-term rate of return on plan assets	6.50%	6.50%	6.00%
Rate of compensation increase	3.51%	3.51%	3.51%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.53%	3.82%	4.49%

EMPLOYEE BENEFIT PLANS Table 10

EMPLOYEE BENEFIT PLANS Table 10 - Assumptions - Health Care Cost Trend Rates (Details) - Other Postretirement Benefit Plans [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
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
Effect of one percentage point increase, description	The cap on the increase in employer’s cost is 2.5% per year. The assumed increase in total health care cost exceeds the 2.5% indexed cap, so increasing or decreasing the health care cost trend rate by 1% does not materially change our obligation or expense for the postretirement health care plan.

UNIT-BASED COMPENSATION Narrati

UNIT-BASED COMPENSATION Narrative 1 (Details) - shares	Dec. 31, 2019	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	2,230,392

UNIT-BASED COMPENSATION Table 1

UNIT-BASED COMPENSATION Table 1 - Information for LTIP Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	1,456,296	1,277,480	902,911
Compensation expense	$ 37,940	$ 30,699	$ 8,727
Restricted units, domestic employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	1,223,143	1,028,484	736,746	647,340
Compensation expense	$ 9,437	$ 8,233	$ 7,881
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	61,349	59,752	27,097
Compensation expense	$ 774	$ 524	$ 251
Restricted units, international employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	10,243	30,918	58,107
Compensation expense	$ 711	$ 1,158	$ 595
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, outstanding (units)	74,439	80,690	38,865	35,373
Compensation expense	$ 4,172	$ 1,889	$ 0
Performance units awarded and outstanding	161,561	158,326	80,961	77,014
Share-based Payment Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 22,846	$ 18,895	$ 0
Performance units awarded and outstanding	0	0	0

UNIT-BASED COMPENSATION Narra_2

UNIT-BASED COMPENSATION Narrative 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash payments made in connection with DERs	$ 2,659	$ 2,045	$ 2,965
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	307,009
Unit-based awards, vested (units)		235,746	201,466
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation, vesting period	3 years
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)	5,378
Unit-based awards, vested (units)	26,053

UNIT-BASED COMPENSATION Table 2

UNIT-BASED COMPENSATION Table 2 - Restricted Unit Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,277,480	902,911
Unit-based awards, ending balance (units)	1,456,296	1,277,480	902,911
Restricted units, domestic employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,028,484	736,746	647,340
Unit based awards, converted (units)		53,447
Unit-based awards, granted (units)		518,282	307,009
Unit-based awards, vested (units)		(235,746)	(201,466)
Unit-based awards, forfeited (units)		(44,245)	(16,137)
Unit-based awards, ending balance (units)	1,223,143	1,028,484	736,746
Weighted-average grant date fair value, period start	$ 29.47	$ 35.95	$ 39.72
Weighted-average grant date fair value, converted		24.99
Weighted-average grant date fair value (per unit), granted		24.07	29.56
Weighted-average grant date fair value, vested		35.12	38.74
Weighted-average grant date fair value, forfeited		36.05	40
Weighted-average grant date fair value, period end		$ 29.47	$ 35.95
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	59,752	27,097
Unit-based awards, adoption of accounting pronouncement	59,752
Unit-based awards, ending balance (units)	61,349	59,752	27,097
Weighted-average grant date fair value, adoption of accounting pronouncement	$ 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, granted (units)	596,881
Unit-based awards, vested (units)	(328,386)
Unit-based awards, forfeited (units)	(72,239)
Unit-based awards, ending balance (units)	1,284,492
Weighted-average grant date fair value (per unit), granted	$ 26.46
Weighted-average grant date fair value, vested	30.11
Weighted-average grant date fair value, forfeited	28.05
Weighted-average grant date fair value, period end	$ 27.48

UNIT-BASED COMPENSATION Narra_3

UNIT-BASED COMPENSATION Narrative 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ 9.3	$ 6.2	$ 6.5
Units issued to satisfy award vestings, net of tax (units)	242,199	189,399	152,017
Unrecognized compensation cost	$ 32.5
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	$ 2.1		$ 2.9
Units issued to satisfy award vestings, net of tax (units)	50,054		33,438
Unit-based compensation, description of performance units	Performance units are issued to certain of our key employees and represent rights to receive our common units upon achieving performance measures for the performance period established by the NuStar GP, LLC Compensation Committee for the following year. Achievement of the performance measures determines the rate at which the performance units convert into our common units, which ranges from zero to 200% for certain awards.
Unit-based compensation, terms of performance units	Performance units awarded vest in three annual increments (tranches), based upon our achievement of the performance measures set by the Compensation Committee during the one-year performance periods that end on December 31 of each applicable year.
Unit-based compensation, requisite service period	1 year

UNIT-BASED COMPENSATION Table 3

UNIT-BASED COMPENSATION Table 3 - Summary of Performance Units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based awards, beginning balance (units)	1,277,480	902,911
Unit-based awards, ending balance (units)	1,456,296	1,277,480	902,911
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units awarded and outstanding, period start	158,326	80,961	77,014
Performance units awarded	95,969	116,230	39,320
Additional performance units awarded			17,690
Unit-based awards, vested (units)	(80,690)	0	(53,063)
Performance units forfeited	(12,044)	(38,865)
Performance units awarded and outstanding, period end	161,561	158,326	80,961
Unit-based awards, beginning balance (units)	80,690	38,865	35,373
Unit-based awards, granted (units)	74,439	80,690	38,865
Additional unit-based awards, granted (units)			17,690
Unit-based awards, forfeited (units)	0	(38,865)
Unit-based awards, ending balance (units)	74,439	80,690	38,865
Weighted-average grant date fair value, period start	$ 23.43	$ 50.04	$ 31.75
Weighted-average grant date fair value (per unit), granted	28.01	23.43	50.04
Weighted-average grant date fair value of additional units, granted			31.75
Weighted-average grant date fair value, vested	23.43		31.75
Weighted-average grant date fair value, forfeited	0	50.04
Weighted-average grant date fair value, period end	$ 28.01	$ 23.43	$ 50.04

UNIT-BASED COMPENSATION Narra_4

UNIT-BASED COMPENSATION Narrative 4 (Details) - Performance Units [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units issued to satisfy award vestings, net of tax (units)	50,054		33,438
Total fair value of restricted units that vested during the period	$ 2.1		$ 2.9
Unit-based awards, vested (units)	(80,690)	0	(53,063)

UNIT-BASED COMPENSATION Table 4

UNIT-BASED COMPENSATION Table 4 - Unit Awards (Details) - USD ($) $ in Thousands	Feb. 11, 2020	Nov. 26, 2019	Feb. 11, 2019	Jul. 23, 2018	Jun. 29, 2018	Apr. 18, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement [Member]
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 February of the subsequent years. 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
Unit-based awards, granted (units)			704,886	55,133
Common Limited Partner [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of units (units)		527,426			413,736	14,375,000	527,426	413,736	14,375,000
Common Limited Partner [Member] | Share-based Payment Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of units (units)			482,971	35,745
Subsequent Event [Member] | Share-based Payment Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value, granted	$ 22,846
Unit-based awards, granted (units)	822,979
Subsequent Event [Member] | Common Limited Partner [Member] | Share-based Payment Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of units (units)	563,806

INCOME TAXES Table 1 - Componen

INCOME TAXES Table 1 - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
U.S.	$ 3,741	$ 4,515	$ 3,117
Foreign	1,489	4,658	6,335
Foreign withholding tax	101	192	479
Total current	5,331	9,365	9,931
Deferred:
U.S.	(490)	1,403	1,468
Foreign	(168)	394	(1,065)
Foreign withholding tax	182	246	(397)
Total deferred	(476)	2,043	6
Less: amounts reported in discontinued operations	101	1,251	2,164
Income tax expense	$ 4,754	$ 10,157	$ 7,773

INCOME TAXES Narrative 1 (Detai

INCOME TAXES Narrative 1 (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation percent	21.00%	21.00%	35.00%

INCOME TAXES Table 2 - Tax Effe

INCOME TAXES Table 2 - Tax Effects of Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
Net operating losses	$ 26,081	$ 21,009
Employee benefits	372	362
Environmental and legal reserves	267	239
Allowance for bad debt	0	1,970
Capital loss	3,870	0
Other	328	1,796
Total deferred income tax assets	30,918	25,376
Less: Valuation allowance	(17,743)	(12,442)
Net deferred income tax assets	13,175	12,934
Deferred income tax liabilities:
Property, plant and equipment	(25,169)	(25,128)
Foreign withholding tax	(433)	(234)
Total deferred income tax liabilities	(25,602)	(25,362)
Net deferred income tax liability	(12,427)	(12,428)
Reported on the Consolidated Balance Sheets as:
Deferred income tax liability	$ (12,427)	$ (12,428)

INCOME TAXES Narrative 2 - Oper

INCOME TAXES Narrative 2 - Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2019USD ($)
U.S. [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 96.8
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 19.1

INCOME TAXES Narrative 3 (Detai

INCOME TAXES Narrative 3 (Details) $ in Millions	Dec. 31, 2019USD ($)
U.S. [Member]
Capital Loss Carryforwards [Line Items]
Capital loss carryforward	$ 18.4

INCOME TAXES Narrative 4 (Detai

INCOME TAXES Narrative 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 17,743	$ 12,442
U.S. [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	3,700
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 1,600

SEGMENT INFORMATION Table 1 - R

SEGMENT INFORMATION Table 1 - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense									272,924	255,892	228,192
Operating income (loss):
Less general and administrative expenses									107,855	100,067	107,556
Less other depreciation and amortization expense									272,924	255,892	228,192
Total operating income (loss)	$ 124,056	$ 99,972	$ 93,283	$ 73,605	$ 86,683	$ 89,165	$ 76,387	$ 83,493	390,916	335,728	290,510
Pipeline Segment
Revenues:
Revenues									701,830	611,065	516,288
Pipeline Segment | Third Party Revenue [Member]
Revenues:
Revenues									701,830	611,065	516,288
Storage Segment
Revenues:
Revenues									454,001	443,588	443,016
Storage Segment | Third Party Revenue [Member]
Revenues:
Revenues									453,976	443,546	438,677
Storage Segment | Intersegment revenue [Member]
Revenues:
Revenues									25	42	4,339
Fuels Marketing Segment | Third Party Revenue [Member]
Revenues:
Revenues									342,215	465,651	489,807
Operating Segments [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense									264,564	247,288	219,757
Operating income (loss):
Less other depreciation and amortization expense									264,564	247,288	219,757
Total operating income (loss)									507,131	444,399	406,501
Operating Segments [Member] | Pipeline Segment
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense									166,991	153,943	128,061
Operating income (loss):
Less other depreciation and amortization expense									166,991	153,943	128,061
Total operating income (loss)									332,480	272,695	231,795
Operating Segments [Member] | Storage Segment
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense									97,573	93,345	91,696
Operating income (loss):
Less other depreciation and amortization expense									97,573	93,345	91,696
Total operating income (loss)									154,105	155,708	172,720
Operating Segments [Member] | Fuels Marketing Segment
Operating income (loss):
Total operating income (loss)									20,578	15,964	1,987
Intersegment Eliminations [Member]
Revenues:
Revenues									(25)	(42)	(4,339)
Operating income (loss):
Total operating income (loss)									(32)	32	(1)
Corporate, Non-Segment [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation and amortization expense									8,360	8,604	8,435
Operating income (loss):
Less general and administrative expenses									107,855	100,067	107,556
Less other depreciation and amortization expense									$ 8,360	$ 8,604	$ 8,435

SEGMENT INFORMATION Table 2 - R

SEGMENT INFORMATION Table 2 - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues By Geographic Areas
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
United States
Revenues By Geographic Areas
Revenues									1,465,135	1,481,844	1,406,776
Foreign
Revenues By Geographic Areas
Revenues									$ 32,886	$ 38,418	$ 37,996

SEGMENT INFORMATION Narrative (

SEGMENT INFORMATION Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Major Customer [Line Items]
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Revenue Benchmark [Member] | Valero Energy Corporation [Member]
Revenue, Major Customer [Line Items]
Largest customer percentage of revenue									21.00%	20.00%	20.00%
Revenues									$ 307,200	$ 303,700	$ 294,500

SEGMENT INFORMATION Table 3 - P

SEGMENT INFORMATION Table 3 - Property, Plant, and Equipment, Net, by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Long-Lived Assets By Geographic Areas
Long-lived assets	$ 4,118,979	$ 3,774,802
United States
Long-Lived Assets By Geographic Areas
Long-lived assets	4,000,647	3,688,631
Foreign
Long-Lived Assets By Geographic Areas
Long-lived assets	$ 118,332	$ 86,171

SEGMENT INFORMATION Table 4 - A

SEGMENT INFORMATION Table 4 - Assets by Reportable Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Information
Total consolidated assets	$ 6,185,992	$ 6,349,140
Operating Segments [Member]
Segment Information
Total consolidated assets	5,998,715	5,577,242
Operating Segments [Member] | Pipeline Segment
Segment Information
Total consolidated assets	3,884,819	3,637,226
Operating Segments [Member] | Storage Segment
Segment Information
Total consolidated assets	2,082,832	1,902,764
Operating Segments [Member] | Fuels Marketing Segment
Segment Information
Total consolidated assets	31,064	37,252
Operating Segments [Member] | Other partnership assets
Segment Information
Total consolidated assets	187,277	172,551
Segment Reconciling Items [Member]
Segment Information
Total consolidated assets	$ 0	$ 599,347

SEGMENT INFORMATION Table 5 - C

SEGMENT INFORMATION Table 5 - Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Information
Capital expenditures	$ 533,568	$ 494,954	$ 1,846,357
Pipeline Segment
Segment Information
Capital expenditures	387,702	288,035	1,596,311
Storage Segment
Segment Information
Capital expenditures	141,972	202,782	244,398
Corporate, Non-Segment [Member]
Segment Information
Capital expenditures	3,894	4,137	5,648
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Segment Information
Capital expenditures, discontinued operations	$ 27,954	$ 114,811	$ 153,785

CONDENSED CONSOLIDATING FINAN_3

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Narrative (Details) - NuStar Energy	12 Months Ended
	Dec. 31, 2019
NuPOP
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	100.00%
NuStar Logistics
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	100.00%

CONDENSED CONSOLIDATING FINAN_4

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Table 1 - Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 16,192	$ 11,529
Receivables, net	152,530	110,417
Inventories	12,393	8,434
Prepaid and other current assets	21,933	17,374
Assets held for sale	0	599,347
Intercompany receivable	0	0
Total current assets	203,048	747,101
Property, plant and equipment, net	4,118,979	3,774,802
Intangible assets, net	681,632	733,056
Goodwill	1,005,853	1,005,853	$ 1,008,667
Investment in wholly owned subsidiaries	0	0
Other long-term assets, net	176,480	88,328
Total assets	6,185,992	6,349,140
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	109,834	103,122
Short-term debt and current portion of finance leases	10,046	18,500
Current portion of long-term debt	452,367	0
Accrued interest payable	37,925	36,293
Accrued liabilities	104,285	74,418
Taxes other than income tax	12,781	16,823
Income tax payable	4,325	4,445
Liabilities held for sale	0	69,834
Intercompany payable	0	0
Total current liabilities	731,563	323,435
Long-term debt, less current portion	2,934,918	3,111,996
Deferred income tax liability	12,427	12,428
Other long-term liabilities	148,939	79,558
Series D preferred units	581,935	563,992	0	$ 0
Total partners' equity	1,776,210	2,257,731	$ 2,480,089	$ 1,611,617
Total liabilities, mezzanine equity and partners’ equity	6,185,992	6,349,140
Eliminations
Assets
Cash and cash equivalents	0	0
Receivables, net	0	0
Inventories	0	0
Prepaid and other current assets	0	0
Assets held for sale		0
Intercompany receivable	(1,887,137)	(1,828,416)
Total current assets	(1,887,137)	(1,828,416)
Property, plant and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Investment in wholly owned subsidiaries	(6,261,287)	(7,388,660)
Other long-term assets, net	0	0
Total assets	(8,148,424)	(9,217,076)
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	0	0
Short-term debt and current portion of finance leases	0	0
Current portion of long-term debt	0
Accrued interest payable	0	0
Accrued liabilities	0	0
Taxes other than income tax	0	0
Income tax payable	0	0
Liabilities held for sale		0
Intercompany payable	(1,887,137)	(1,828,416)
Total current liabilities	(1,887,137)	(1,828,416)
Long-term debt, less current portion	0	0
Deferred income tax liability	0	0
Other long-term liabilities	0	0
Series D preferred units	0	0
Total partners' equity	(6,261,287)	(7,388,660)
Total liabilities, mezzanine equity and partners’ equity	(8,148,424)	(9,217,076)
Parent Company Guarantor [Member] | NuStar Energy | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	176	1,255
Receivables, net	0	0
Inventories	0	0
Prepaid and other current assets	61	61
Assets held for sale		0
Intercompany receivable	0	0
Total current assets	237	1,316
Property, plant and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Investment in wholly owned subsidiaries	2,871,540	3,355,636
Other long-term assets, net	98	304
Total assets	2,871,875	3,357,256
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	5,427	6,460
Short-term debt and current portion of finance leases	0	0
Current portion of long-term debt	0
Accrued interest payable	0	0
Accrued liabilities	1,425	1,280
Taxes other than income tax	125	125
Income tax payable	0	0
Liabilities held for sale		0
Intercompany payable	438,857	472,790
Total current liabilities	445,834	480,655
Long-term debt, less current portion	0	0
Deferred income tax liability	0	0
Other long-term liabilities	0	0
Series D preferred units	581,935	563,992
Total partners' equity	1,844,106	2,312,609
Total liabilities, mezzanine equity and partners’ equity	2,871,875	3,357,256
Subsidiary Issuer [Member] | NuStar Logistics | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	24	51
Receivables, net	317	2,212
Inventories	1,953	1,741
Prepaid and other current assets	16,325	14,422
Assets held for sale		0
Intercompany receivable	1,276,839	1,327,833
Total current assets	1,295,458	1,346,259
Property, plant and equipment, net	2,058,530	1,858,264
Intangible assets, net	39,683	49,107
Goodwill	149,453	149,453
Investment in wholly owned subsidiaries	1,743,066	1,750,256
Other long-term assets, net	111,362	54,429
Total assets	5,397,552	5,207,768
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	42,064	39,680
Short-term debt and current portion of finance leases	9,722	18,500
Current portion of long-term debt	452,367
Accrued interest payable	37,888	36,253
Accrued liabilities	40,514	24,858
Taxes other than income tax	7,311	7,285
Income tax payable	492	457
Liabilities held for sale		0
Intercompany payable	0	0
Total current liabilities	590,358	127,033
Long-term debt, less current portion	2,871,786	3,050,531
Deferred income tax liability	1,499	1,675
Other long-term liabilities	65,577	28,392
Series D preferred units	0	0
Total partners' equity	1,868,332	2,000,137
Total liabilities, mezzanine equity and partners’ equity	5,397,552	5,207,768
Guarantor Subsidiaries [Member] | NuPOP | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	0	0
Receivables, net	4	0
Inventories	4,821	5,237
Prepaid and other current assets	600	908
Assets held for sale		0
Intercompany receivable	0	0
Total current assets	5,425	6,145
Property, plant and equipment, net	612,128	615,549
Intangible assets, net	0	0
Goodwill	170,652	170,652
Investment in wholly owned subsidiaries	1,155,855	1,425,283
Other long-term assets, net	32,121	26,716
Total assets	1,976,181	2,244,345
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	8,379	6,331
Short-term debt and current portion of finance leases	299	0
Current portion of long-term debt	0
Accrued interest payable	4	0
Accrued liabilities	8,461	8,082
Taxes other than income tax	5,160	4,718
Income tax payable	2	2
Liabilities held for sale		0
Intercompany payable	1,448,280	1,355,626
Total current liabilities	1,470,585	1,374,759
Long-term debt, less current portion	1,127	0
Deferred income tax liability	10	9
Other long-term liabilities	13,774	12,348
Series D preferred units	0	0
Total partners' equity	490,685	857,229
Total liabilities, mezzanine equity and partners’ equity	1,976,181	2,244,345
Non-Guarantor Subsidiaries | Reportable Legal Entities [Member]
Assets
Cash and cash equivalents	15,992	10,223
Receivables, net	152,209	108,205
Inventories	5,619	1,456
Prepaid and other current assets	4,947	1,983
Assets held for sale		599,347
Intercompany receivable	610,298	500,583
Total current assets	789,065	1,221,797
Property, plant and equipment, net	1,448,321	1,300,989
Intangible assets, net	641,949	683,949
Goodwill	685,748	685,748
Investment in wholly owned subsidiaries	490,826	857,485
Other long-term assets, net	32,899	6,879
Total assets	4,088,808	4,756,847
Liabilities, Mezzanine Equity and Partners' Equity
Accounts payable	53,964	50,651
Short-term debt and current portion of finance leases	25	0
Current portion of long-term debt	0
Accrued interest payable	33	40
Accrued liabilities	53,885	40,198
Taxes other than income tax	185	4,695
Income tax payable	3,831	3,986
Liabilities held for sale		69,834
Intercompany payable	0	0
Total current liabilities	111,923	169,404
Long-term debt, less current portion	62,005	61,465
Deferred income tax liability	10,918	10,744
Other long-term liabilities	69,588	38,818
Series D preferred units	0	0
Total partners' equity	3,834,374	4,476,416
Total liabilities, mezzanine equity and partners’ equity	$ 4,088,808	$ 4,756,847

CONDENSED CONSOLIDATING FINAN_5

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Table 2 - Condensed Consolidating Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Costs and expenses									1,107,105	1,184,534	1,154,262
Operating income (loss)	124,056	99,972	93,283	73,605	86,683	89,165	76,387	83,493	390,916	335,728	290,510
Equity in earnings (loss) of subsidiaries									0	0	0
Interest income (expense), net									(183,070)	(184,398)	(171,774)
Other income (expense), net									3,742	5,202	(68)
Income (loss) from continuing operations before income tax expense (benefit)									211,588	156,532	118,668
Income tax (benefit) expense									4,754	10,157	7,773
Income (loss) from continuing operations, net of tax	78,408	52,588	46,915	28,923	42,570	43,663	26,909	33,233	206,834	146,375	110,895
Income (loss) from discontinued operations, net of tax	0	(4,777)	(964)	(306,786)	(40,444)	4,473	2,490	92,900	(312,527)	59,419	37,069
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133	(105,693)	205,794	147,964
Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenues									(747)	(705)	(1,018)
Costs and expenses									(747)	(705)	(1,018)
Operating income (loss)									0	0	0
Equity in earnings (loss) of subsidiaries									(447,037)	(381,045)	(276,057)
Interest income (expense), net									0	0	0
Other income (expense), net									0	0	0
Income (loss) from continuing operations before income tax expense (benefit)									(447,037)	(381,045)	(276,057)
Income tax (benefit) expense									0	0	0
Income (loss) from continuing operations, net of tax									(447,037)	(381,045)	(276,057)
Income (loss) from discontinued operations, net of tax									953,404	(178,257)	(111,207)
Net income (loss)									506,367	(559,302)	(387,264)
Parent Company Guarantor [Member] | NuStar Energy | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									0	0	0
Costs and expenses									2,574	2,407	1,868
Operating income (loss)									(2,574)	(2,407)	(1,868)
Equity in earnings (loss) of subsidiaries									208,995	148,554	112,706
Interest income (expense), net									415	228	57
Other income (expense), net									0	0	0
Income (loss) from continuing operations before income tax expense (benefit)									206,836	146,375	110,895
Income tax (benefit) expense									2	0	0
Income (loss) from continuing operations, net of tax									206,834	146,375	110,895
Income (loss) from discontinued operations, net of tax									(312,527)	59,419	37,069
Net income (loss)									(105,693)	205,794	147,964
Subsidiary Issuer [Member] | NuStar Logistics | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									545,863	485,603	496,454
Costs and expenses									338,291	317,286	317,871
Operating income (loss)									207,572	168,317	178,583
Equity in earnings (loss) of subsidiaries									42,139	17,167	(10,616)
Interest income (expense), net									(187,337)	(191,835)	(176,897)
Other income (expense), net									3,002	3,876	145
Income (loss) from continuing operations before income tax expense (benefit)									65,376	(2,475)	(8,785)
Income tax (benefit) expense									(230)	588	(820)
Income (loss) from continuing operations, net of tax									65,606	(3,063)	(7,965)
Income (loss) from discontinued operations, net of tax									7,912	0	0
Net income (loss)									73,518	(3,063)	(7,965)
Guarantor Subsidiaries [Member] | NuPOP | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									258,420	260,679	221,125
Costs and expenses									159,376	163,667	146,243
Operating income (loss)									99,044	97,012	74,882
Equity in earnings (loss) of subsidiaries									51,537	62,494	52,336
Interest income (expense), net									(6,961)	(7,127)	(5,587)
Other income (expense), net									744	446	3
Income (loss) from continuing operations before income tax expense (benefit)									144,364	152,825	121,634
Income tax (benefit) expense									3	(3)	2
Income (loss) from continuing operations, net of tax									144,361	152,828	121,632
Income (loss) from discontinued operations, net of tax									(320,439)	59,419	37,069
Net income (loss)									(176,078)	212,247	158,701
Non-Guarantor Subsidiaries | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues									694,485	774,685	728,211
Costs and expenses									607,611	701,879	689,298
Operating income (loss)									86,874	72,806	38,913
Equity in earnings (loss) of subsidiaries									144,366	152,830	121,631
Interest income (expense), net									10,813	14,336	10,653
Other income (expense), net									(4)	880	(216)
Income (loss) from continuing operations before income tax expense (benefit)									242,049	240,852	170,981
Income tax (benefit) expense									4,979	9,572	8,591
Income (loss) from continuing operations, net of tax									237,070	231,280	162,390
Income (loss) from discontinued operations, net of tax									(640,877)	118,838	74,138
Net income (loss)									$ (403,807)	$ 350,118	$ 236,528

CONDENSED CONSOLIDATING FINAN_6

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Table 3 - Condensed Consolidating Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133	$ (105,693)	$ 205,794	$ 147,964
Other comprehensive income (loss):
Foreign currency translation adjustment									3,527	4,304	17,466
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									(1,314)	2,334	(6,170)
Net (loss) gain on cash flow hedges									(15,231)	23,411	(2,046)
Total other comprehensive income (loss)									(13,018)	30,049	9,250
Comprehensive income (loss)									(118,711)	235,843	157,214
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									506,367	(559,302)	(387,264)
Other comprehensive income (loss):
Foreign currency translation adjustment									0	0	0
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									0	0	0
Net (loss) gain on cash flow hedges									0	0	0
Total other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									506,367	(559,302)	(387,264)
Parent Company Guarantor [Member] | NuStar Energy | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									(105,693)	205,794	147,964
Other comprehensive income (loss):
Foreign currency translation adjustment									0	0	0
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									0	0	0
Net (loss) gain on cash flow hedges									0	0	0
Total other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									(105,693)	205,794	147,964
Subsidiary Issuer [Member] | NuStar Logistics | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									73,518	(3,063)	(7,965)
Other comprehensive income (loss):
Foreign currency translation adjustment									0	0	0
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									0	0	0
Net (loss) gain on cash flow hedges									(15,231)	23,411	(2,046)
Total other comprehensive income (loss)									(15,231)	23,411	(2,046)
Comprehensive income (loss)									58,287	20,348	(10,011)
Guarantor Subsidiaries [Member] | NuPOP | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									(176,078)	212,247	158,701
Other comprehensive income (loss):
Foreign currency translation adjustment									0	0	0
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									0	0	0
Net (loss) gain on cash flow hedges									0	0	0
Total other comprehensive income (loss)									0	0	0
Comprehensive income (loss)									(176,078)	212,247	158,701
Non-Guarantor Subsidiaries | Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									(403,807)	350,118	236,528
Other comprehensive income (loss):
Foreign currency translation adjustment									3,527	4,304	17,466
Net (loss) gain on pension and other postretirement benefit adjustments, net of tax benefit (expense)									(1,314)	2,334	(6,170)
Net (loss) gain on cash flow hedges									0	0	0
Total other comprehensive income (loss)									2,213	6,638	11,296
Comprehensive income (loss)									$ (401,594)	$ 356,756	$ 247,824

CONDENSED CONSOLIDATING FINAN_7

CONDENSED CONSOLIDATING FINANCIAL STATEMENTS Table 4 - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	Nov. 26, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net cash provided by (used in) operating activities		$ 508,757	$ 544,207	$ 406,799
Cash flows from investing activities:
Capital expenditures		(533,568)	(457,452)	(384,638)
Change in accounts payable related to capital expenditures		(12,731)	(7,683)	36,903
Acquisitions		0	(37,502)	(1,461,719)
Proceeds from Axeon term loan		0	0	110,000
Proceeds from insurance recoveries		0	78,419	977
Proceeds from sale or disposition of assets		228,152	270,440	2,036
Investment in subsidiaries		0	0	0
Other, net		(1,100)	0	0
Net cash (used in) provided by investing activities		(319,247)	(153,778)	(1,696,441)
Cash flows from financing activities:
Debt borrowings		1,458,380	1,872,653	3,060,100
Debt repayments		(1,249,400)	(2,381,776)	(2,487,539)
Proceeds from issuance of Series D preferred units		0	590,000	0
Payment of issuance costs for Series D preferred units		0	(34,203)	0
Proceeds from issuance of other preferred units, net of issuance costs		0	0	538,560
Proceeds from issuance of common units, net of issuance costs	$ 15,000	15,000	10,000	643,878
Contributions from general partner		0	204	13,737
Distributions to preferred unitholders		(121,693)	(90,670)	(38,833)
Distributions to common unitholders and general partner		(258,354)	(300,777)	(446,306)
Cash consideration for Merger (Note 4)		0	(67,795)	0
Proceeds from termination of interest rate swaps		0	8,048	0
Contributions from (distributions to) affiliates		0	0	0
Net intercompany activity		0	0	0
Other, net		(21,583)	(5,551)	(7,325)
Net cash provided by (used in) financing activities		(177,650)	(399,867)	1,276,272
Effect of foreign exchange rate changes on cash		(524)	(1,210)	1,720
Net increase (decrease) in cash, cash equivalents and restricted cash		11,336	(10,648)	(11,650)
Cash, cash equivalents and restricted cash as of the beginning of the period		13,644	24,292	35,942
Cash, cash equivalents and restricted cash as of the end of the period		24,980	13,644	24,292
Eliminations
Cash flows from operating activities:
Net cash provided by (used in) operating activities		(570,090)	(694,859)	(737,138)
Cash flows from investing activities:
Capital expenditures		0	0	0
Change in accounts payable related to capital expenditures		0	0	0
Acquisitions			0	0
Proceeds from Axeon term loan				0
Proceeds from insurance recoveries			0	0
Proceeds from sale or disposition of assets		0	0	0
Investment in subsidiaries		11,999	2,529,840	1,262,126
Other, net		0
Net cash (used in) provided by investing activities		11,999	2,529,840	1,262,126
Cash flows from financing activities:
Debt borrowings		0	0	0
Debt repayments		0	0	0
Proceeds from issuance of Series D preferred units			0
Payment of issuance costs for Series D preferred units			0
Proceeds from issuance of other preferred units, net of issuance costs				0
Proceeds from issuance of common units, net of issuance costs		0	0	0
Contributions from general partner			0	0
Distributions to preferred unitholders		182,546	136,007	58,251
Distributions to common unitholders and general partner		387,544	451,184	669,482
Cash consideration for Merger (Note 4)			0
Proceeds from termination of interest rate swaps			0
Contributions from (distributions to) affiliates		(11,999)	(2,422,172)	(1,252,721)
Net intercompany activity		0	0	0
Other, net		0	0	0
Net cash provided by (used in) financing activities		558,091	(1,834,981)	(524,988)
Effect of foreign exchange rate changes on cash		0	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash		0	0	0
Cash, cash equivalents and restricted cash as of the beginning of the period		0	0	0
Cash, cash equivalents and restricted cash as of the end of the period		0	0	0
Parent Company Guarantor [Member] | NuStar Energy | Reportable Legal Entities [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		376,999	444,233	483,481
Cash flows from investing activities:
Capital expenditures		0	0	0
Change in accounts payable related to capital expenditures		0	0	0
Acquisitions			0	0
Proceeds from Axeon term loan				0
Proceeds from insurance recoveries			0	0
Proceeds from sale or disposition of assets		0	0	0
Investment in subsidiaries		0	(708,600)	(1,262,000)
Other, net		0
Net cash (used in) provided by investing activities		0	(708,600)	(1,262,000)
Cash flows from financing activities:
Debt borrowings		0	0	0
Debt repayments		0	0	0
Proceeds from issuance of Series D preferred units			590,000
Payment of issuance costs for Series D preferred units			(34,203)
Proceeds from issuance of other preferred units, net of issuance costs				538,560
Proceeds from issuance of common units, net of issuance costs		15,000	10,000	643,878
Contributions from general partner			204	13,737
Distributions to preferred unitholders		(121,693)	(90,670)	(38,833)
Distributions to common unitholders and general partner		(258,354)	(300,777)	(446,306)
Cash consideration for Merger (Note 4)			(67,936)
Proceeds from termination of interest rate swaps			0
Contributions from (distributions to) affiliates		0	0	0
Net intercompany activity		(2,010)	162,498	73,206
Other, net		(11,021)	(4,379)	(5,708)
Net cash provided by (used in) financing activities		(378,078)	264,737	778,534
Effect of foreign exchange rate changes on cash		0	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash		(1,079)	370	15
Cash, cash equivalents and restricted cash as of the beginning of the period		1,255	885	870
Cash, cash equivalents and restricted cash as of the end of the period		176	1,255	885
Subsidiary Issuer [Member] | NuStar Logistics | Reportable Legal Entities [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		166,005	100,385	152,101
Cash flows from investing activities:
Capital expenditures		(257,117)	(71,044)	(47,600)
Change in accounts payable related to capital expenditures		1,369	11,101	(1,988)
Acquisitions			0	0
Proceeds from Axeon term loan				110,000
Proceeds from insurance recoveries			0	0
Proceeds from sale or disposition of assets		247	2,674	1,955
Investment in subsidiaries		(11,999)	(1,711,975)	0
Other, net		0
Net cash (used in) provided by investing activities		(267,500)	(1,769,244)	62,367
Cash flows from financing activities:
Debt borrowings		1,415,580	1,840,853	2,969,400
Debt repayments		(1,207,000)	(2,349,476)	(2,400,739)
Proceeds from issuance of Series D preferred units			0
Payment of issuance costs for Series D preferred units			0
Proceeds from issuance of other preferred units, net of issuance costs				0
Proceeds from issuance of common units, net of issuance costs		0	0	0
Contributions from general partner			0	0
Distributions to preferred unitholders		(60,846)	(45,336)	(19,417)
Distributions to common unitholders and general partner		(129,177)	(150,388)	(223,153)
Cash consideration for Merger (Note 4)			0
Proceeds from termination of interest rate swaps			8,048
Contributions from (distributions to) affiliates		0	599,400	1,262,000
Net intercompany activity		101,980	1,766,881	(1,801,218)
Other, net		(10,281)	(1,101)	(1,317)
Net cash provided by (used in) financing activities		110,256	1,668,881	(214,444)
Effect of foreign exchange rate changes on cash		0	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash		8,761	22	24
Cash, cash equivalents and restricted cash as of the beginning of the period		51	29	5
Cash, cash equivalents and restricted cash as of the end of the period		8,812	51	29
Guarantor Subsidiaries [Member] | NuPOP | Reportable Legal Entities [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		126,728	179,512	102,405
Cash flows from investing activities:
Capital expenditures		(28,592)	(19,152)	(35,041)
Change in accounts payable related to capital expenditures		1,212	(5,161)	5,964
Acquisitions			(37,502)	0
Proceeds from Axeon term loan				0
Proceeds from insurance recoveries			0	0
Proceeds from sale or disposition of assets		90	31	18
Investment in subsidiaries		0	(54,600)	0
Other, net		0
Net cash (used in) provided by investing activities		(27,290)	(116,384)	(29,059)
Cash flows from financing activities:
Debt borrowings		0	0	0
Debt repayments		0	0	0
Proceeds from issuance of Series D preferred units			0
Payment of issuance costs for Series D preferred units			0
Proceeds from issuance of other preferred units, net of issuance costs				0
Proceeds from issuance of common units, net of issuance costs		0	0	0
Contributions from general partner			0	0
Distributions to preferred unitholders		(60,847)	(45,336)	(19,416)
Distributions to common unitholders and general partner		(129,177)	(150,388)	(223,153)
Cash consideration for Merger (Note 4)			0
Proceeds from termination of interest rate swaps			0
Contributions from (distributions to) affiliates		0	54,600	0
Net intercompany activity		90,734	77,996	169,223
Other, net		(148)	0	0
Net cash provided by (used in) financing activities		(99,438)	(63,128)	(73,346)
Effect of foreign exchange rate changes on cash		0	0	0
Net increase (decrease) in cash, cash equivalents and restricted cash		0	0	0
Cash, cash equivalents and restricted cash as of the beginning of the period		0	0	0
Cash, cash equivalents and restricted cash as of the end of the period		0	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		409,115	514,936	405,950
Cash flows from investing activities:
Capital expenditures		(247,859)	(367,256)	(301,997)
Change in accounts payable related to capital expenditures		(15,312)	(13,623)	32,927
Acquisitions			0	(1,461,719)
Proceeds from Axeon term loan				0
Proceeds from insurance recoveries			78,419	977
Proceeds from sale or disposition of assets		227,815	267,735	63
Investment in subsidiaries		0	(54,665)	(126)
Other, net		(1,100)
Net cash (used in) provided by investing activities		(36,456)	(89,390)	(1,729,875)
Cash flows from financing activities:
Debt borrowings		42,800	31,800	90,700
Debt repayments		(42,400)	(32,300)	(86,800)
Proceeds from issuance of Series D preferred units			0
Payment of issuance costs for Series D preferred units			0
Proceeds from issuance of other preferred units, net of issuance costs				0
Proceeds from issuance of common units, net of issuance costs		0	0	0
Contributions from general partner			0	0
Distributions to preferred unitholders		(60,853)	(45,335)	(19,418)
Distributions to common unitholders and general partner		(129,190)	(150,408)	(223,176)
Cash consideration for Merger (Note 4)			141
Proceeds from termination of interest rate swaps			0
Contributions from (distributions to) affiliates		11,999	1,768,172	(9,279)
Net intercompany activity		(190,704)	(2,007,375)	1,558,789
Other, net		(133)	(71)	(300)
Net cash provided by (used in) financing activities		(368,481)	(435,376)	1,310,516
Effect of foreign exchange rate changes on cash		(524)	(1,210)	1,720
Net increase (decrease) in cash, cash equivalents and restricted cash		3,654	(11,040)	(11,689)
Cash, cash equivalents and restricted cash as of the beginning of the period		12,338	23,378	35,067
Cash, cash equivalents and restricted cash as of the end of the period		$ 15,992	$ 12,338	$ 23,378

QUARTERLY FINANCIAL DATA - Tabl

QUARTERLY FINANCIAL DATA - Table - Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Revenues	$ 399,694	$ 378,056	$ 372,445	$ 347,826	$ 374,137	$ 380,142	$ 389,256	$ 376,727	$ 1,498,021	$ 1,520,262	$ 1,444,772
Operating income (loss)	124,056	99,972	93,283	73,605	86,683	89,165	76,387	83,493	390,916	335,728	290,510
Income (loss) from continuing operations, net of tax	78,408	52,588	46,915	28,923	42,570	43,663	26,909	33,233	206,834	146,375	110,895
Income (loss) from discontinued operations, net of tax	0	(4,777)	(964)	(306,786)	(40,444)	4,473	2,490	92,900	(312,527)	59,419	37,069
Net income (loss)	$ 78,408	$ 47,811	$ 45,951	$ (277,863)	$ 2,126	$ 48,136	$ 29,399	$ 126,133	$ (105,693)	$ 205,794	$ 147,964
Basic net income (loss) per common unit
Basic net income (loss) per common unit from continuing operations	$ 0.40	$ 0.15	$ 0.11	$ (0.06)	$ 0.07	$ (3.53)	$ 0.12	$ 0.18	$ 0.60	$ (3.34)	$ 0.23
Basic net income (loss) per common unit from discontinued operations	0	(0.04)	(0.01)	(2.85)	(0.38)	0.04	0.03	0.97	(2.90)	0.57	0.41
Total net income (loss) per common unit	0.40	0.11	0.10	(2.91)	(0.31)	(3.49)	0.15	1.15	(2.30)	(2.77)	0.64
Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted [Abstract]
Diluted net (loss) income per common unit from continuing operations	0.40	0.15	0.11	(0.06)	0.07	(3.53)	0.12	0.18	0.60	(3.34)	0.23
Diluted net (loss) income per common unit from discontinued operations	0	(0.04)	(0.01)	(2.85)	(0.38)	0.04	0.03	0.97	(2.90)	0.57	0.41
Total net income (loss) per common unit	0.40	0.11	0.10	(2.91)	(0.31)	(3.49)	0.15	1.15	(2.30)	(2.77)	0.64
Common Limited Partner [Member]
Distribution Made to Limited Partner [Line Items]
Cash distributions per unit applicable to limited partners	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 2.40	$ 2.40	$ 4.38
Quarterly Financial Data [Abstract]
Net income (loss)									$ (227,386)	$ 110,788	$ 60,610

QUARTERLY FINANCIAL DATA (UNA_3

QUARTERLY FINANCIAL DATA (UNAUDITED) Narrative (Details) - USD ($)	Oct. 01, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset impairment losses		$ 8,400,000	$ 297,300,000	$ 305,700,000
Goodwill impairment loss	$ 0
(Gain) loss, property damage				0	$ (78,756,000)	$ 0
Loss to common unitholders attributable to the Merger				0	(377,079,000)	0
Hurricane damage at St. Eustatius terminal [Member] | (Loss) income from discontinued operations, net of tax [Member]
(Gain) loss, property damage					(78,800,000)	5,000,000
The European Disposition [Member]
Non-cash loss on sale of assets				$ 0	$ (43,366,000)	$ 0
St. Eustatius Bunkers [Member]
Goodwill impairment loss			$ 31,100,000