v3.10.0.1

PARTNERS' EQUITY (Tables)

9 Months Ended

Sep. 30, 2018

Distributions Made to Limited Partners and General Partner [Line Items]

Schedule of Changes in Partners' Equity [Table Text Block]

The following table summarizes changes to our partners’ equity, which excludes the carrying value of the Series D Preferred Units (in thousands of dollars):

Balance as of January 1, 2018	$	2,480,089
Net income	189,608
Unit-based compensation	6,559
Other comprehensive income	23,204
Distributions to partners	(284,605		)
Issuance of common units, including contribution from general partner	10,204
Adjustments related to the Merger (refer to Note 2 for discussion)	(67,972		)
Series D Preferred Unit accretion (refer to Note 11 for discussion)	(4,031		)
Other	(6,174		)
Balance as of September 30, 2018	$	2,346,882

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:

	Three Months Ended September 30,								Nine Months Ended September 30,
	2018				2017				2018				2017
	(Thousands of Dollars, Except Per Unit Data)
General partner interest	$	—			$	2,302			$	1,141			$	6,947
General partner incentive distribution	—				10,912				—				34,736
Total general partner distribution	—				13,214				1,141				41,683
Common limited partners’ distribution	64,248				101,870				184,369				305,652
Total cash distributions	$	64,248			$	115,084			$	185,510			$	347,335
Cash distributions per unit applicable to common limited partners	$	0.60			$	1.095			$	1.800			$	3.285

Distributions Made to Common Limited and General Partners, by Distribution [Table Text Block]

The following table summarizes information about our quarterly cash distributions to our general partner, prior to the Merger, and to our common limited partners:

Quarter Ended		Cash Distributions Per Unit				Total Cash Distributions				Record Date		Payment Date
						(Thousands of Dollars)
September 30, 2018		$	0.600			$	64,248			November 8, 2018		November 14, 2018
June 30, 2018		$	0.600			$	64,205			August 7, 2018		August 13, 2018
March 31, 2018		$	0.600			$	57,057			May 8, 2018		May 14, 2018
December 31, 2017		$	1.095			$	115,267			February 8, 2018		February 13, 2018

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

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

	Foreign Currency Translation				Cash Flow Hedges				Pension and Other Postretirement Benefits				Total
	(Thousands of Dollars)
Balance as of January 1, 2018	$	(51,603	)		$	(24,304	)		$	(9,020	)		$	(84,927	)
Other comprehensive (loss) income:
Other comprehensive (loss) income before reclassification adjustments	(6,536		)		26,067				—				19,531
Net gain on pension costs reclassified into other income, net	—				—				(611		)		(611		)
Net loss on cash flow hedges reclassified into interest    expense, net	—				4,271				—				4,271
Other	60				—				(47		)		13
Other comprehensive (loss) income	(6,476		)		30,338				(658		)		23,204
Balance as of September 30, 2018	$	(58,079	)		$	6,034			$	(9,678	)		$	(61,723	)

Preferred 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 our cash distributions on our 8.50% Series A, 7.625% Series B and 9.00% Series C Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units:

Period		Cash Distributions Per Unit				Total Cash Distributions				Record Date		Payment Date
						(Thousands of Dollars)
Series A Preferred Units:
September 15, 2018 - December 14, 2018		$	0.53125			$	4,813			December 3, 2018		December 17, 2018
June 15, 2018 - September 14, 2018		$	0.53125			$	4,813			September 4, 2018		September 17, 2018
March 15, 2018 - June 14, 2018		$	0.53125			$	4,813			June 1, 2018		June 15, 2018
December 15, 2017 - March 14, 2018		$	0.53125			$	4,813			March 1, 2018		March 15, 2018
Series B Preferred Units:
September 15, 2018 - December 14, 2018		$	0.47657			$	7,339			December 3, 2018		December 17, 2018
June 15, 2018 - September 14, 2018		$	0.47657			$	7,339			September 4, 2018		September 17, 2018
March 15, 2018 - June 14, 2018		$	0.47657			$	7,339			June 1, 2018		June 15, 2018
December 15, 2017 - March 14, 2018		$	0.47657			$	7,339			March 1, 2018		March 15, 2018
Series C Preferred Units:
September 15, 2018 to December 14, 2018		$	0.56250			$	3,881			December 3, 2018		December 17, 2018
June 15, 2018 to September 14, 2018		$	0.56250			$	3,881			September 4, 2018		September 17, 2018
March 15, 2018 to June 14, 2018		$	0.56250			$	3,881			June 1, 2018		June 15, 2018
November 30, 2017 - March 14, 2018		$	0.65625			$	4,528			March 1, 2018		March 15, 2018

X

- Definition

Tabular disclosure of payment of cash made to common limited and general partners of a limited partnership (LP).

+ References

No definition available.

+ Details

Name:	ns_DistributionsMadeToCommonLimitedAndGeneralPartnersByDistributionTableTextBlock
Namespace Prefix:	ns_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Distributions Made to Limited Partners and General Partner [Line Items]

+ References

No definition available.

+ Details

Name:	ns_DistributionsMadeToLimitedPartnersAndGeneralPartnerLineItems
Namespace Prefix:	ns_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Schedule describing the distribution waterfall.

+ References

No definition available.

+ Details

Name:	ns_ScheduleOfDistributionWaterfallTableTextBlock
Namespace Prefix:	ns_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Schedule of Distributions To General and Common Limited Partners [Table Text Block]

+ References

No definition available.

+ Details

Name:	ns_ScheduleofDistributionsToGeneralandCommonLimitedPartnersTableTextBlock
Namespace Prefix:	ns_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of payment of cash or stock made to limited partner of limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_DistributionsMadeToLimitedPartnerByDistributionTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the components of accumulated other comprehensive income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669686-108580

+ Details

Name:	us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of changes in the separate accounts comprising stockholders' equity (in addition to retained earnings) and of the changes in the number of shares of equity securities during at least the most recent annual fiscal period and any subsequent interim period presented is required to make the financial statements sufficiently informative if both financial position and results of operations are presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

+ Details

Name:	us-gaap_ScheduleOfStockholdersEquityTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=ns_SeriesASeriesBAndSeriesCPreferredLimitedPartnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: