REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 34,146	$ 40,869	[1]
Gas gathering and compression
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	4,335	5,720
Gas processing
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	23,195	29,896
Transmission
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	3,157	4,175
NGL transmission
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	528	826
Other
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	314	150
Service
Disaggregation of Revenue [Line Items]
Midstream services revenue — affiliate	31,529	40,767	[1]
Product
Disaggregation of Revenue [Line Items]
Product sales — third parties	$ 2,617	$ 102	[1]

[1] This period presented has been revised to reflect the Company’s fair value change of its underlying warrants. Refer to Note 1—Summary of Significant Accounting Policies, see the section titled Revision of Previously Issued Consolidated Financial Statements for Immaterial Adjustment for further information.