MEMBERS' EQUITY Table 3 (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Our cash distributions applicable to the period in which the distributions were earned
Cash distributions per unit	$ 0.545	$ 0.545	$ 0.545
Total cash distributions	$ 23,248	$ 23,249	$ 23,222

Distribution amount per limited liability company member unit outstanding earned during the period, and to be paid in the subsequent quarter.

No definition available.

Name:	nsh_DistributionPerLimitedLiabilityCompanyLLCMemberUnitOutstanding
Namespace Prefix:	nsh_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration