MEMBERS' EQUITY Narrative (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Distributions (dates and totals)
Total cash distributions, paid	$ (21,708)		$ (20,422)
Cash distributions per unit, paid		$ 0.51
Cash distributions, payment date	May 15, 2012	Feb. 14, 2012
Total cash distributions, earned	$ 21,720		$ 20,422
Cash distributions per unit, declared	$ 0.51		$ 0.48
Cash distributions, record date	May 08, 2012