v3.8.0.1

PARTNERS' EQUITY Narrative 1 (Details) | 3 Months Ended
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Mar. 31, 2018
Class of Stock [Line Items] |
Percent of available cash distributed | 100.00%
Number of days within which distribution Is paid to common unitholder and general partner | 45
Series A Preferred Limited Partner [Member] |
Class of Stock [Line Items] |
Preferred units distribution percentage | 8.50%
Series B Preferred Limited Partner [Member] |
Class of Stock [Line Items] |
Preferred units distribution percentage | 7.625%
Series C Preferred Limited Partner [Member] |
Class of Stock [Line Items] |
Preferred units distribution percentage | 9.00%

X
- Definition Number of days within which distribution must be paid to common unitholders and the general partner after end of quarter (per the terms of the partnership agreement). + References No definition available. + Details
Name: | ns_NumberofDaysWithinWhichDistributionIsPaidToCommonUnitholderAndGeneralPartner
Namespace Prefix: | ns_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent of available cash distributed to partners (per the terms of the partnership agreement). + References No definition available. + Details
Name: | ns_PercentOfAvailableCashDistributed
Namespace Prefix: | ns_
Data Type: | num:percentItemType
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 percentage rate used to calculate dividend payments on preferred stock. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
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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: |