RELATED PARTY TRANSACTIONS Table (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Related Party Transaction [Line Items]
Expenses for payroll, employee benefit plans and unit-based compensation	$ 52,905	$ 58,953
Other	$ 93	$ 96

Related party transactions for payroll, employee benefit plans and unit-based compensation charged to equity method investee.

No definition available.

Name:	nsh_RelatedPartyTransactionExpensesFromTransactionsWithRelatedPartyPayrollAndBenefits
Namespace Prefix:	nsh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration