Supplemental Oil and Natural Gas Information (unaudited) - Changes in Standardized Measure of Discounted Net Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves [Roll Forward]
Standardized Measure, beginning of the year	$ 1,329,310	$ 729,686	$ 205,981
Net change in prices and production costs	(531,056)	369,578	653,347
Net change in future development costs	28,481	87,466	(385,042)
Sales, less production costs	(327,373)	(321,802)	(226,324)
Extensions	251,343	363,708	135,734
Acquisitions	387,117	7,468	2,365
Divestitures		(20)
Revisions of previous quantity estimates	7,345	19,910	322,917
Previously estimated development costs incurred	245,931	65,035	34,102
Net changes in taxes	(237,482)	(37,345)
Accretion of discount	132,931	72,969	20,598
Changes in timing and other	(90,723)	(27,343)	(33,992)
Standardized Measure, end of year	$ 1,195,824	$ 1,329,310	$ 729,686