FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross fair value, assets	$ 0	$ 6,362
Effect of Counterparty Netting, Assets	0	(5,213)
Total net carrying value on balance sheet, assets	0	1,149
Gross fair value, liabilities	128,932	26,379
Effect of counterparty netting, liabilities	0	(5,213)
Total net carrying value on balance sheet, liabilities	128,932	21,166
Commodity Derivative Instruments | Fair Value Measurements, Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Effect of Counterparty Netting, Assets	0	(5,213)
Total net carrying value on balance sheet, assets	0	1,149
Effect of counterparty netting, liabilities	0	(5,213)
Total net carrying value on balance sheet, liabilities	128,932	21,166
Commodity Derivative Instruments | Fair Value Measurements, Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross fair value, assets	0	0
Gross fair value, liabilities	0	0
Commodity Derivative Instruments | Fair Value Measurements, Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross fair value, assets	0	6,362
Gross fair value, liabilities	128,932	26,379
Commodity Derivative Instruments | Fair Value Measurements, Recurring Basis | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross fair value, assets	0	0
Gross fair value, liabilities	$ 0	$ 0