v3.8.0.1

UNIT-BASED COMPENSATION Narrative 2 (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Related party expense, long-term incentive plan |  |  | $ 6,400
Cash payments made in connection with DERs | $ 2,965 | $ 2,697 | $ 0

X
- Definition Company's share of compensation expense related to various long-term incentive plans provided to employees of the general partner (who provide services to the company). + References No definition available. + Details
Name: | ns_RelatedPartyExpenseLongTermIncentivePlans
Namespace Prefix: | ns_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of paid and unpaid cash dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units. + References No definition available. + Details
Name: | us-gaap_DividendsShareBasedCompensationCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration