SUPPLEMENTAL DISCLOSURES - Summary of Current Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	$ 151,051	$ 119,158
Accrued evaluated and unproved and unevaluated property costs
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	61,813	44,012
Accrued midstream properties costs
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	4,957	12,776
Accrued lease operating expenses
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	30,833	24,276
Accrued interest on debt
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	18,385	18,315
Accrued asset retirement obligations
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	211	623
Accrued partners’ share of joint interest charges
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	8,129	7,407
Accrued payable related to purchased natural gas
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	1,813	418
Other
Condensed Balance Sheet Statements, Captions [Line Items]
Total accrued liabilities	$ 24,910	$ 11,331