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EQUITY METHOD INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Asset contribution to an equity method investment				$ 23,643	$ 0
Cash distribution to partnership				7,252	0
Additional cash investments				11,300
Impairment loss		$ 677	$ 1,169	1,197	$ 3,703
Principal Owner
Schedule Of Equity Method Investments [Line Items]
Cash distribution to partnership				7,300
Double E
Schedule Of Equity Method Investments [Line Items]
Net assets	$ 28,300	28,300		28,300
Result of operations		$ 0		0
Double E \| Principal Owner
Schedule Of Equity Method Investments [Line Items]
Asset contribution to an equity method investment				$ 23,600
Percentage of ownership interest	70.00%	70.00%		70.00%
Double E \| JV Partner
Schedule Of Equity Method Investments [Line Items]
Percentage of ownership interest	30.00%	30.00%		30.00%
Cash contribution				$ 7,300
OGC \| Summit Midstream Partners, LLC
Schedule Of Equity Method Investments [Line Items]
Impairment loss	$ 757
OGC \| Principal Owner
Schedule Of Equity Method Investments [Line Items]
Percentage of ownership interest	38.80%	38.80%		38.80%		40.00%