Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Detail) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Natural gas properties:
Properties subject to depletion	[1]	$ 9,447,907	$ 9,338,236
Unproved properties	[1]	843,612	837,334
Total	[1]	10,291,519	10,175,570
Accumulated depletion and depreciation	[1]	(4,504,554)	(4,420,914)
Natural gas and oil properties, successful efforts method, net	[1]	$ 5,786,965	$ 5,754,656

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