MEMBERS' EQUITY Table 3 (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 24, 2017	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 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
Total cash distributions (distribution earned)		$ 23,409	$ 23,408	$ 23,397
Distribution date of record (distribution earned)		May 08, 2017	Feb. 08, 2017
Distribution payment date (distribution earned)		May 16, 2017	Feb. 15, 2017
Subsequent Event [Member]
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Distribution announcement date (distribution earned)	Apr. 24, 2017