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).

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No definition available.

+ Details

Name:	ns_ConversionRateOfCommonUnitsForMerger
Namespace Prefix:	ns_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- 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.

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No definition available.

+ Details

Name:	ns_GeneralPartnerOwnershipInterest
Namespace Prefix:	ns_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage investment held by Greehey Unitholders in NuStar GP, LLC.

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No definition available.

+ Details

Name:	ns_GreeheyUnitholdersOwnershipPercentage
Namespace Prefix:	ns_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of Common Limited Partner Units Owned by General Partner

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No definition available.

+ Details

Name:	ns_NumberofCommonLimitedPartnerUnitsOwnedbyGeneralPartner
Namespace Prefix:	ns_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration