Accounts Receivable and Major Customers - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cost of Goods and Services Sold		$ 22,050	$ 23,197	$ 18,626
Net Income (Loss) Available to Common Stockholders, Basic	$ 224,785	(310,557)	70,589	224,785
Customers		39,672	63,165
Joint interest partners		3,079	6,929
Other		8	674
Accounts Receivable, Gross, Current, Total		42,759	70,768
Less: Allowance for credit losses		(197)	(52)
Accounts receivable, net of allowance for doubtful accounts		42,562	70,716
Oil and Gas, Exploration and Production [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		251,741	434,713	402,485
Oil and Condensate [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		8,948	16,589	21,073
Natural Gas, Production [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		$ 10,103	$ 17,733	$ 15,972