MEMBERS' EQUITY Table 4 (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended					9 Months Ended
	Oct. 30, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	$ 0.545	$ 0.545	$ 1.635	$ 1.635
Total cash distributions (distribution earned)		$ 23,388	$ 23,388	$ 23,388	$ 23,403	$ 23,351	$ 70,164	$ 69,849
Distribution date of record (distribution earned)		Nov. 09, 2015	Aug. 07, 2015	May 08, 2015	Feb. 09, 2015
Distribution payment date (distribution earned)		Nov. 17, 2015	Aug. 17, 2015	May 18, 2015	Feb. 17, 2015
Subsequent Event [Member]
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Distribution announcement date (distribution earned)	Oct. 30, 2015