MEMBERS' EQUITY Table 3 (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended
	Jul. 28, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
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	$ 1.090	$ 1.090
Total cash distributions (distribution earned)		$ 23,408	$ 23,409	$ 23,408	$ 23,398	$ 46,817	$ 46,795
Distribution date of record (distribution earned)		Aug. 07, 2017	May 08, 2017	Feb. 08, 2017
Distribution payment date (distribution earned)		Aug. 15, 2017	May 16, 2017	Feb. 15, 2017
Subsequent Event [Member]
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Distribution announcement date (distribution earned)	Jul. 28, 2017