MEMBERS' EQUITY Narrative 1 (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Distributions (description, dates and totals)
Cash distributions, timing description		Our limited liability company agreement requires that, within 50 days after the end of each quarter, we distribute all of our available cash to the holders of record of our units on the applicable record date.
Cash distributions, payment date	Feb. 19, 2013
Total cash distributions, paid	$ 23,200	$ 88,345	$ 82,966	$ 77,589
Cash distributions per unit, paid	$ 0.545