Derivative Financial Instruments - Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions (Detail) bbl in Thousands, MMBTU in Thousands, $ in Thousands	Mar. 31, 2021 USD ($) bbl MMBTU	Dec. 31, 2020 USD ($) bbl MMBTU
Financial Institution Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	4,620	3,056
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	8,906	6,391
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 9,176	$ 8,341
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (74,039)	$ (32,112)
Financial Institution Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	2,422	9,281
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	17,857	15,079
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 448	$ 1,529
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (3,835)	$ (3,265)
Customer Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	8,906	6,391
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	4,620	3,056
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 74,932	$ 32,670
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (8,897)	$ (8,264)
Customer Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	17,857	17,636
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	2,422	6,724
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 4,048	$ 3,451
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (444)	$ (1,458)