DERIVATIVE FINANCIAL INSTRUMENTS - Summary of Location and Aggregate Fair Value of All Derivative Financial Instruments Recorded in the Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instrument
Realized (loss) gain on derivatives	$ (42,611)	$ 44,110	$ (68,524)	$ 54,977
Unrealized (loss) gain on derivatives	(42,804)	(132,668)	(86,227)	3,762
Total	(85,415)	(88,558)	(154,751)	58,739
Revenues
Derivative Instrument
Realized (loss) gain on derivatives	(42,611)	44,110	(68,524)	54,977
Unrealized (loss) gain on derivatives	(42,804)	(132,668)	(86,227)	3,762
Oil | Revenues
Derivative Instrument
Realized (loss) gain on derivatives	(42,611)	44,110	(68,686)	54,977
Unrealized (loss) gain on derivatives	(35,163)	(134,567)	(74,432)	1,863
Natural Gas | Revenues
Derivative Instrument
Realized (loss) gain on derivatives	0	0	162	0
Unrealized (loss) gain on derivatives	$ (7,641)	$ 1,899	$ (11,795)	$ 1,899