SUPPLEMENTAL OIL AND GAS INFORMATION (UNAUDITED) - Additional Information (Details) - Oil Boe in Thousands	12 Months Ended
	Dec. 31, 2019 Boe MMBoe	Dec. 31, 2019 Boe MMBoe	Dec. 31, 2018 MMBoe Boe	Dec. 31, 2018 Boe MMBoe	Dec. 31, 2017 MMBoe Boe	Dec. 31, 2017 Boe MMBoe	Dec. 31, 2016 Boe
Reserve Quantities [Line Items]
Extension and discoveries attributable to successful drilling (in MMBOE) | Boe		23,662		33,241		24,791
Proved Developed Reserves | Boe	96,634	96,634	76,216	76,216	46,346	46,346	37,713
Proved Undeveloped Reserves | Boe	66,673	66,673	59,268	59,268	29,487	29,487	16,368
Purchase of mineral in place (in MMBOE)	34.6	34,606	32.2	32,198
Increase (decrease) to proved reserves	(16.4)	(16,355)	3.5	3,541	2.4	2,363
Upward (downward) adjustment attributable to lower crude oil and natural gas prices (in MMBOE)	(9.8)		1.4		1.8
Downward adjustment due to well performance (in MMBOE)	(2.0)		3.9		3.1
Downward adjustment attributable to removal of undeveloped drilling locations (in MMBOE)	(4.6)		(4.4)		2.5
Williston Basin
Reserve Quantities [Line Items]
Extension and discoveries attributable to successful drilling (in MMBOE)	23.7		33.2		24.8
Proved Developed Reserves	11.3	11.3	20.9	20.9	5.9	5.9
Additional Locations
Reserve Quantities [Line Items]
Proved Developed Reserves	12.3	12.3
Proved Undeveloped Reserves			12.3	12.3	18.9	18.9