RELATED PARTY TRANSACTIONS - Summary of related party transactions (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) well	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Total	$ (37,677)	$ 12,592
Varde Partners, Inc.
Related Party Transaction [Line Items]
Number of wells operated (in wells) \| well	2
The Company acquired oil and natural gas interests from VPD, an affiliate of Värde	$ 0	10,705
Receivable balance outstanding for operating costs associated with VPD's producing wells	0	1,843
ImPetro Operating, LLC, a wholly-owned subsidiary of the Company is the operator for two of VPD's producing wells and VPD reimbursed the Company for operating charges	0	44
Payable to WLR for net proportionate share of production	(157)	0
WLR
Related Party Transaction [Line Items]
Payable to WLR for net proportionate share of production	(161)	0
WLWI
Related Party Transaction [Line Items]
Payable to WLR for net proportionate share of production	(526)
Asset disposition accounted for as a financing arrangement \| Varde Partners, Inc.
Related Party Transaction [Line Items]
Total	$ (36,833)	$ 0

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