v3.8.0.1

MERGER AGREEMENT Narrative (Details) - shares | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Feb. 07, 2018
Business Combinations [Abstract] |  |  |
General partner ownership interest | 2.00% | 2.00% |
Common unit conversion rate |  |  | 55.00%
NuStar Energy common units owned by NuStar GP Holdings | 10,214,626 |  |
Greehey Unitholders ownership interest |  |  | 21.00%

X
- Definition Rate applied to the conversion of outstanding common units at the effective time of the merger (percent of acquirer's common unit to be exchanged per acquiree unit). + References No definition available. + Details
Name: | ns_ConversionRateOfCommonUnitsForMerger
Namespace Prefix: | ns_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

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- Definition The general partner ownership interest (ownership percentage) in the limited partnership. Excludes other ownership interests held by the general partner in the limited partnership. + References No definition available. + Details
Name: | ns_GeneralPartnerOwnershipInterest
Namespace Prefix: | ns_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Percentage investment held by Greehey Unitholders in NuStar GP, LLC. + References No definition available. + Details
Name: | ns_GreeheyUnitholdersOwnershipPercentage
Namespace Prefix: | ns_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Definition Number of Common Limited Partner Units Owned by General Partner + References No definition available. + Details
Name: | ns_NumberofCommonLimitedPartnerUnitsOwnedbyGeneralPartner
Namespace Prefix: | ns_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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- References No definition available. + Details
Name: | us-gaap_BusinessCombinationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration