v3.20.2

ORGANIZATION AND BASIS OF PRESENTATION Narrative 3 (Details) - USD ($) $ in Thousands |  | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Oct. 15, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Unusual or Infrequent Item, or Both [Line Items] |  |  |  |  |
Goodwill impairment loss |  | $ 0 | $ 0 | $ 225,000 | $ 0
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 |  |  |  |
Selby, California Fire [Member] |  |  |  |  |
Unusual or Infrequent Item, or Both [Line Items] |  |  |  |  |
Insurance proceeds received |  |  |  | 35,000 |
Selby, California Fire [Member] | Business Interruption Loss from Selby, California Fire [Member] | Operating Expense [Member] |  |  |  |  |
Unusual or Infrequent Item, or Both [Line Items] |  |  |  |  |
Gain from business interruption insurance |  | $ 3,600 |  | $ 6,700 |

X
- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13854-109267 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of insurance proceeds for an event or transaction that is unusual in nature or infrequent in occurrence, or both. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=114868883&loc=SL114871943-224233 + Details
Name: | us-gaap_UnusualOrInfrequentItemInsuranceProceeds
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_UnusualOrInfrequentItemLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the nature of an event or transaction that is unusual in nature or infrequent in occurrence, or both. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=114868883&loc=SL114871943-224233 + Details
Name: | us-gaap_UnusualOrInfrequentItemNatureOfEventOrTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of (gain) loss for an event or transaction that is unusual in nature or occurs infrequently, or both. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 270 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109227538&loc=d3e44648-109337 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=114868879&loc=SL114871939-224231 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=114868883&loc=SL114871943-224233 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 + Details
Name: | us-gaap_UnusualOrInfrequentItemNetGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_UnusualOrInfrequentItemAxis=ns_SelbyCaliforniaFireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessInterruptionLossAxis=ns_BusinessInterruptionLossfromSelbyCaliforniaFireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_OperatingExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |