Derivative Financial Instruments - Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions (Detail) bbl in Thousands, MMBTU in Thousands, $ in Thousands	Sep. 30, 2021 USD ($) MMBTU bbl	Dec. 31, 2020 USD ($) bbl MMBTU
Financial Institution Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	5,632	3,056
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	12,228	6,391
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 21,271	$ 8,341
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (147,576)	$ (32,112)
Financial Institution Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	18,908	9,281
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	39,901	15,079
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 3,312	$ 1,529
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (53,923)	$ (3,265)
Customer Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	12,276	6,391
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	5,584	3,056
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 148,742	$ 32,670
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (21,245)	$ (8,264)
Customer Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	39,901	17,636
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	18,908	6,724
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 54,202	$ 3,451
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (3,310)	$ (1,458)