PARTNERS' CAPITAL AND DISTRIBUTIONS - Narrative (Details) - Limited Partners - Equity Distribution Agreements - USD ($) shares in Millions	1 Months Ended		9 Months Ended
	Mar. 31, 2016	May 31, 2013	Sep. 30, 2016
Partner's capital and distributions
LP Units authorized to sell (in shares)	$ 500,000,000.0	$ 300,000,000.0
Public offering, LP units issued (in shares)			1.6
Proceeds from issuance of units			$ 108,400,000
Aggregate compensation expense paid to the agents under the Equity Distribution Agreements			$ 1,100,000