Supplemental Information on Natural Gas and Oil Exploration, Development and Production Activities (Unaudited) - Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Natural gas and oil properties:
Properties subject to depletion	[1]	$ 9,338,236	$ 8,891,348	$ 9,345,557
Unproved properties	[1]	837,334	859,766	868,180
Total	[1]	10,175,570	9,751,114	10,213,737
Accumulated depreciation, depletion and amortization	[1]	(4,420,914)	(4,064,305)	(4,172,702)
Natural gas and oil properties, successful efforts method, net	[1]	$ 5,754,656	$ 5,686,809	$ 6,041,035

[1] Includes capitalized asset retirement costs and the associated accumulated amortization.