MEMBERS' EQUITY Table 1 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Changes to our members’ equity
Balance as of December 31, 2012	$ 412,822
Net income (loss)	11,075		11,046
Distributions to unitholders	(23,223)	(23,200)	(21,708)
Other Comprehensive Income (Loss), Net of Tax	197
Unit-based compensation	(55)
Balance as of March 31, 2013	$ 400,816	$ 412,822