Summary of Property and Equipment (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / bbl	Dec. 31, 2018 USD ($) $ / bbl	Dec. 31, 2017 USD ($) $ / bbl	Dec. 31, 2016 USD ($)
Property, Plant and Equipment [Abstract]
Proved Oil and Gas Property, Full Cost Method	$ 1,409,219	$ 1,037,993
Undeveloped Leasehold Costs Transferred	16,800	82,800
Interest Costs Capitalized	$ 4,100	$ 9,100	$ 2,700
Amortization Expense Per Physical Unit of Production | $ / bbl	17.25	16.11	12.87
Unproved Oil and Gas Property excluded	$ 53,200	$ 63,500
Capitalized Exploratory Well Costs		300
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	1,300	6,100	$ 43,100	$ 2,700
Capitalized Costs, Proved Properties	4,100	3,700	$ 2,400
Oil and gas properties:
Unproved Oil and Gas Property, Full Cost Method	53,200	63,484
Oil and Gas Property, Full Cost Method, Gross	1,462,419	1,101,477
Other property and equipment	25,915	20,383
Total property and equipment	1,488,334	1,121,860
Accumulated depreciation, depletion and amortization	(367,909)	(193,866)
Property and equipment, net (successful efforts method)	$ 1,120,425	$ 927,994