SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 442,842	$ 147,416	$ 779,023	$ 371,704
Lease bonus - mineral acreage	0	4,062	0	4,062
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 revenues	357,427	62,920	624,272	434,505
Oil revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	315,114	94,174	528,393	263,759
Natural gas revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	96,960	24,593	199,914	52,922
Third-party midstream services revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	19,850	14,668	35,288	30,498
Sales of purchased natural gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 10,918	$ 13,981	$ 15,428	$ 24,525