MEMBERS' EQUITY Table 1 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in Members' Equity [Roll Forward]
Balance as of December 31, 2013			$ 349,986
Net income (loss)	15,768	12,559	29,414	23,634
Distributions to unitholders			(46,497)	(46,445)
Other comprehensive income (loss)			(930)
Unit-based compensation			128
Balance as of June 30, 2014	$ 332,101		$ 332,101