Supplemental Information on Natural Gas and Oil Exploration, Development and Production Activities (Unaudited) - Proved Developed and Undeveloped Reserves (Detail)		12 Months Ended
		Dec. 31, 2021 MMcfe MMBbls MMcf	Dec. 31, 2020 MMcfe MMBbls MMcf	Dec. 31, 2019 MMcfe MMcf MMBbls
Proved undeveloped reserves:
Proved undeveloped reserves | MMcfe		7,357,597	7,410,574
Natural Gas
Reserve Quantities [Line Items]
Beginning Balance | MMcf		11,148,560	12,114,977	12,027,702
Revisions | MMcf		(311,410)	(789,992)	33,122
Extensions, discoveries and additions | MMcf		1,155,952	1,007,415	959,901
Property sales | MMcf			(609,311)	(327,634)
Production | MMcf		(541,021)	(574,529)	(578,114)
Ending Balance | MMcf		11,452,081	11,148,560	12,114,977
Proved developed reserves:
Proved developed reserves | MMcf		6,809,849	6,350,057	6,486,211
Proved undeveloped reserves:
Proved undeveloped reserves | MMcf		4,642,232	4,798,503	5,628,766
NGLs
Reserve Quantities [Line Items]
Beginning Balance		951,466	938,236	921,594
Revisions		16,845	42,741	57,311
Extensions, discoveries and additions		69,367	38,298	26,505
Property sales			(30,317)	(28,324)
Production		(36,373)	(37,492)	(38,850)
Ending Balance		1,001,305	951,466	938,236
Proved developed reserves:
Proved developed reserves		577,506	550,771	535,007
Proved undeveloped reserves:
Proved undeveloped reserves		423,798	400,695	403,229
Crude Oil and Condensate
Reserve Quantities [Line Items]
Beginning Balance		57,626	74,532	85,856
Revisions		(7,089)	(12,444)	(12,320)
Extensions, discoveries and additions		5,103	4,512	7,057
Property sales			(6,145)	(2,371)
Production		(3,044)	(2,829)	(3,690)
Ending Balance		52,596	57,626	74,532
Proved developed reserves:
Proved developed reserves		23,833	22,976	34,369
Proved undeveloped reserves:
Proved undeveloped reserves		28,762	34,650	40,163
Natural Gas Equivalents
Proved developed reserves:
Proved developed reserves | MMcfe	[1]	10,417,887	9,792,540	9,902,468
Proved undeveloped reserves:
Proved undeveloped reserves | MMcfe	[1]	7,357,597	7,410,574	8,289,115
Beginning Balance | MMcfe	[1]	17,203,114	18,191,583	18,072,406
Revisions | MMcfe	[1]	(252,876)	(608,211)	303,068
Extensions, discoveries and additions | MMcfe	[1]	1,602,769	1,264,282	1,161,274
Property sales | MMcfe	[1]		(828,084)	(511,811)
Production | MMcfe	[1]	(777,523)	(816,456)	(833,354)
Ending Balance | MMcfe	[1]	17,775,484	17,203,114	18,191,583

[1] Oil and NGLs volumes are converted to mcfe at the rate of one barrel equals six mcf based upon the approximate relative energy content of oil to natural gas, which is not indicative of the relationship between oil and natural gas prices.