DISTRIBUTIONS OF AVAILABLE CASH - Quarterly Distributions (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Feb. 17, 2017	Jan. 27, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
DISTRIBUTIONS OF AVAILABLE CASH
Quarterly distribution paid (in dollars per share)	$ 0.55		$ 0.5500	$ 0.5500	$ 0.5500	$ 0.9600	$ 0.9600	$ 0.9600	$ 0.9375	$ 0.9150	$ 0.8925	$ 0.8700	$ 0.8475	$ 0.8275
Distributions declared (in dollars per unit)		$ 0.55
Approximate distribution to be paid (in dollars)		$ 32.9