v3.20.2

PARTNERS' EQUITY Table 1 - Cash Distributions - Preferred Units (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Series A Preferred Limited Partner [Member]
Distribution Made to Preferred Limited Partner [Line Items]
Preferred units distribution percentage			8.50%
Preferred unit distribution	$ 0.53125
Fixed distribution per quarter	$ 4,813
Series B Preferred Limited Partner [Member]
Distribution Made to Preferred Limited Partner [Line Items]
Preferred units distribution percentage			7.625%
Preferred unit distribution	$ 0.47657
Fixed distribution per quarter	$ 7,339
Series C Preferred Limited Partner [Member]
Distribution Made to Preferred Limited Partner [Line Items]
Preferred units distribution percentage			9.00%
Preferred unit distribution	$ 0.56250
Fixed distribution per quarter	$ 3,881
Preferred Limited Partner [Member]
Distribution Made to Preferred Limited Partner [Line Items]
Fixed distribution per quarter	$ 16,033	$ 16,033	$ 32,066	$ 32,066

X

- Definition

Per unit of ownership amount of cash distributions declared to unit-holder of a limited partnership (LP).

+ 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=27012166&loc=d3e187085-122770

Reference 2: 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

Reference 3: 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

+ Details

Name:	us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
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_DistributionMadeToLimitedPartnerLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Total distributions to each class of partners (i.e., 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=27012166&loc=d3e187085-122770

Reference 2: 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=27012166&loc=d3e187171-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountDistributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

+ Details

Name:	us-gaap_PreferredStockDividendRatePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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