v3.8.0.1

SUBSEQUENT EVENTS (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 07, 2018
Subsequent Event [Line Items]
General partner ownership interest		2.00%	2.00%	2.00%
NuStar Energy common units owned by NuStar GP Holdings		10,214,626
Subsequent Event [Member]
Subsequent Event [Line Items]
Common unit conversion rate					55.00%
Greehey Unitholders ownership interest					21.00%
Scenario, Plan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Common limited partner quarterly distribution per unit reset	$ 0.60
Common limited partner quarterly distribution per unit annualized reset	$ 2.40

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

X

- Definition

Expected per unit quarterly distribution annualized to common limited partners to be declared and paid.

+ References

No definition available.

+ Details

Name:	ns_ExpectedPerUnitQuarterlyDistributionAnnualizedToCommonLimitedPartners
Namespace Prefix:	ns_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Expected per unit quarterly distribution to common limited partners to be declared and paid.

+ References

No definition available.

+ Details

Name:	ns_ExpectedPerUnitQuarterlyDistributionToCommonLimitedPartners
Namespace Prefix:	ns_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

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.

+ References

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.

+ References

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

+ References

No definition available.

+ Details

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

X

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: