Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Total property and equipment	$ 7,994,960	$ 8,089,473
Less accumulated depreciation, depletion and impairment	(5,570,235)	(5,328,432)
Property and equipment, net	2,424,725	2,761,041
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	7,559,061	7,647,451
Oil and natural gas properties
Property Plant And Equipment [Line Items]
Total property and equipment	229,224	222,738
Buildings
Property Plant And Equipment [Line Items]
Total property and equipment	182,113	193,503
Land
Property Plant And Equipment [Line Items]
Total property and equipment	$ 24,562	$ 25,781