MEMBERS' EQUITY Table 4 (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Cash distributions per unit applicable to members (distribution earned)	$ 0.545	$ 0.545	$ 0.545
Total cash distributions (distribution earned)	$ 23,248	$ 23,249	$ 23,222
Distribution date of record (distribution earned)	May 07, 2014	Feb. 10, 2014
Distribution payment date (distribution earned)	May 15, 2014	Feb. 18, 2014
Distribution announcement date (distribution earned)	Apr. 23, 2014