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

The ownership of limited partner common units in the investee accounted for under the equity method of accounting.

No definition available.

Name:	nsh_EquityMethodInvestmentOwnershipLimitedPartnerUnits
Namespace Prefix:	nsh_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Incentive Distribution Rights Percentage

No definition available.

Name:	nsh_IncentiveDistributionRightsPercentage
Namespace Prefix:	nsh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Maximum allowable percentage of cash distributed by equity method investee related to incentive distribution rights.

No definition available.

Name:	nsh_IncentiveDistributionRightsPercentageMaximumAllowable
Namespace Prefix:	nsh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

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