SEGMENT INFORMATION - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting [Abstract]
(Loss) income before income taxes and loss from equity method investees	$ (9,947)	$ 58,589	$ (40,183)	$ 7,488
Add:
Corporate and Other expense	7,039	9,324	28,406	28,949
Interest expense	19,335	14,862	54,803	44,821
Deferred Purchase Price Obligation	3,760	(37,204)	11,899	53,759
Depreciation and amortization	27,640	26,592	82,919	79,752
Proportional adjusted EBITDA for equity method investees	10,435	10,171	29,584	29,583
Adjustments related to MVC shortfall payments	3,534	(2,999)	2,868	(6,541)
Adjustments related to capital reimbursement activity	(145)	(106)	(1,906)	49
Unit-based and noncash compensation	1,291	1,965	5,370	6,188
(Gain) loss on asset sales, net	(347)	6	(1,595)	(6)
Long-lived asset impairment	0	1,540	45,021	2,127
Goodwill impairment	16,211	0	16,211	0
Total of reportable segments' measures of profit	$ 78,806	$ 82,740	$ 233,397	$ 246,169