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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instrument
Realized (loss) gain on derivatives	$ (57,419)	$ (5,406)	$ (125,943)	$ 49,571
Unrealized gain (loss) on derivatives	9,049	(13,033)	(77,178)	(9,271)
Total	(48,370)	(18,439)	(203,121)	40,300
Revenues
Derivative Instrument
Realized (loss) gain on derivatives	(57,419)	(5,406)	(125,943)	49,571
Unrealized gain (loss) on derivatives	9,049	(13,033)	(77,178)	(9,271)
Oil | Revenues
Derivative Instrument
Realized (loss) gain on derivatives	(52,774)	(5,406)	(121,460)	49,571
Unrealized gain (loss) on derivatives	38,961	(9,843)	(35,471)	(7,980)
Natural Gas | Revenues
Derivative Instrument
Realized (loss) gain on derivatives	(4,645)	0	(4,483)	0
Unrealized gain (loss) on derivatives	$ (29,912)	$ (3,190)	$ (41,707)	$ (1,291)