v3.20.2

PARTNERS' EQUITY Table 1 - Cash Distributions - Preferred Units (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 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 | $ 16,034 | $ 16,034 | $ 48,100 | $ 48,100

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=120397183&loc=d3e187085-122770 + 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=120397183&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=120397183&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: |