MEMBERS' EQUITY Narrative (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Distributions (dates and totals)
Total cash distributions, paid	$ 23,200		$ 46,445	$ 43,428
Cash distributions per unit, paid	$ 0.545
Distribution Made to Member or Limited Partner, Anouncement Date	Jul. 26, 2013
Cash distributions, payment date	May 15, 2013
Total cash distributions, earned	$ 23,236	$ 21,713	$ 46,458	$ 43,433
Cash distributions per unit, declared	$ 0.545	$ 0.510	$ 1.090	$ 1.020
Distribution payment date	Aug. 14, 2013
Cash distributions, record date	Aug. 05, 2013