MEMBERS' EQUITY Table 1 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes in Members' Equity [Roll Forward]
Balance as of December 31, 2014			$ 310,836
Net income	$ 16,917	$ 17,639	59,249	$ 47,053
Distributions to unitholders			(70,179)	$ (69,747)
Other comprehensive income (loss)			(3,113)
Unit-based compensation			382
Other			15
Balance as of September 30, 2015	$ 297,190		$ 297,190