The percentage of common equity ownership in the equity method investee.

No definition available.

Name:	nsh_EquityMethodInvestmentCommonInterestOwnershipPercentage
Namespace Prefix:	nsh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The profit or loss on sales of previously unissued stock by equity investees made to investors outside the consolidated group that is not reported as operating income. Represents the difference in the parent company's carrying amount of the equity interest in the subsidiary or equity investee immediately before and after the transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_GainOrLossOnSaleOfPreviouslyUnissuedStockByEquityInvestee
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from a borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromShortTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of consideration received by subsidiary or equity investee in exchange for shares of stock issued or sold. Includes amount of cash received, fair value of noncash assets received, and fair value of liabilities assumed by the investor.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockConsiderationReceivedPerTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

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

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=nsh_NuStarEnergyCommonLimitedPartnerUnitIssuance2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=nsh_NuStarEnergySecondaryOfferings2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=nsh_NustarEnergyLpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

INVESTMENT IN NUSTAR ENERGY Narrative 3 (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Apr. 18, 2017	Apr. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investment in NuStar Energy L.P.			$ 13,738	$ 842	$ 7,444
General partner interest percentage			2.00%	2.00%
Common limited partner ownership interest in NuStar Energy			11.00%
Proceeds from short-term debt borrowings			$ 15,500	$ 4,000	$ 0
NuStar Energy Common Limited Partner Unit Issuance 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Investment in NuStar Energy L.P.	$ 13,600
Gain related to NuStar Energy L.P.'s issuance of common limited partner units	$ 41,600
NuStar Energy Common Limited Partner Unit Issuance 2016 [Member]
Schedule of Equity Method Investments [Line Items]
Investment in NuStar Energy L.P.				600
Gain related to NuStar Energy L.P.'s issuance of common limited partner units				$ 2,100
Revolving Credit Facility [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from short-term debt borrowings		$ 14,000
NuStar Energy LP [Member] \| NuStar Energy Common Limited Partner Unit Issuance 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Limited partner units issued by NuStar Energy	14,375,000
Price of common limited partner units issued by NuStar Energy, per unit	$ 46.35
Net proceeds received by NuStar Energy from issuance of units	$ 657,500
NuStar Energy LP [Member] \| NuStar Energy Common Limited Partner Unit Issuance 2016 [Member]
Schedule of Equity Method Investments [Line Items]
Limited partner units issued by NuStar Energy				595,050
Price of common limited partner units issued by NuStar Energy, per unit				$ 47.39
Net proceeds received by NuStar Energy from issuance of units				$ 28,300