MEMBERS' EQUITY Table 4 (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Our cash distributions applicable to the period in which the distributions were earned
Cash distributions per unit	$ 0.545	$ 0.545	$ 0.545	$ 0.545	$ 0.545	$ 1.635	$ 1.565
Total cash distributions	$ 23,231	$ 23,236	$ 23,222	$ 23,223	$ 23,204	$ 69,689	$ 66,637

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

No definition available.

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