Accounts Receivable and Major Customers - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cost of Goods and Services Sold		$ 23,197	$ 18,626	$ 10,734
Net Income (Loss) Available to Common Stockholders, Basic	$ 32,662	70,589	224,785
Customers		63,165	59,030
Joint interest partners		6,929	6,404
Other		674	640
Accounts Receivable, Gross, Current, Total		70,768	66,074
Less: Allowance for doubtful accounts		(52)	(36)
Accounts receivable, net of allowance for doubtful accounts		70,716	66,038
Oil and Gas, Exploration and Production [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		434,713	402,485	140,886
Oil and Condensate [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		16,589	21,073	10,066
Natural Gas, Production [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer		$ 17,733	$ 15,972	$ 8,517