v3.20.4

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

X

- Definition

Conversion of Stock, Incremental Shares Issued

+ References

No definition available.

+ Details

Name:	ns_ConversionofStockIncrementalSharesIssued
Namespace Prefix:	ns_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of limited partner units outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187171-122770

+ Details

Name:	us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Total units issued during the year due to the sale of units. All partners include general, limited and preferred partners.

+ References

Reference 1: 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=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsSaleOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of units issued for unit-based payment arrangement issued by partnership. Partner includes, but is not limited to, general, limited and preferred partners.

+ References

Reference 1: 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=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsUnitbasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Details

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