QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 22,647	$ 28,008	$ 27,912	$ 24,987	$ 47,784	$ 18,803	$ 15,891	$ 17,345
Income (loss) from operations	(2,545)	4,172	3,809	6,957	14,570	1,805	993	12,684	$ 12,636	$ 30,052	$ 5,621
Net and comprehensive income (loss) attributable to unitholders	$ (1,778)	$ 2,644	$ 199	$ 5,718	$ 12,705	$ 1,658	$ 158	$ 3,370	$ 6,821	$ 17,891	$ 5,942
Basic and diluted earnings (loss) per unit (in dollars per share)	$ (0.41)	$ 0.60	$ 0.04	$ 1.31	$ 2.92	$ 0.38	$ 0.03	$ 0.77	$ 1.54	$ 4.10	$ 1.35