v3.10.0.1

MERGER Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jul. 20, 2018
Subsequent Events [Abstract]
General partner ownership interest		2.00%	2.00%	2.00%	2.00%
Number of common limited partner units owned by general partner		10,214,626		10,214,626
Subsequent Event [Member]
Subsequent Event [Line Items]
Common unit conversion rate						55.00%
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Assumed NSH Debt						$ 51.5
Merger, transaction costs						$ 10.0
Estimated effect of merger on net income per common unit	$ (3.55)
Common Limited Partner [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Issuance of NuStar Energy common units as a result of the Merger, units issued	23,600,000
Issuance of NuStar Energy common units as a result of the Merger, incremental units issued	13,400,000

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

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X

- Definition

Conversion of Stock, Incremental Shares Issued

+ References

No definition available.

+ Details

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X

- Definition

Debt assumed in merger transaction

+ References

No definition available.

+ Details

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Balance Type:	credit
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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

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Namespace Prefix:	ns_
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X

- Definition

Number of Common Limited Partner Units Owned by General Partner

+ References

No definition available.

+ Details

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Namespace Prefix:	ns_
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X

- Definition

The estimated effect on earnings per share of a subsequent event

+ References

No definition available.

+ Details

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

X

- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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X

- Definition

The number of new shares issued in the conversion of stock in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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- 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

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- References

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- Details

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X

- Details

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