MEMBERS' EQUITY Table 1 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Members' Equity [Roll Forward]
Balance as of December 31, 2015	$ 287,070
Net income	16,676	$ 26,805
Distributions to unitholders	(23,397)	$ (23,403)
Other comprehensive income (loss)	(6,718)
Unit-based compensation	177
Balance as of March 31, 2016	$ 273,808