Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Total property and equipment	$ 8,218,883	$ 7,129,996
Less accumulated depreciation, depletion and impairment	(3,986,689)	(3,721,033)
Property and equipment, net	4,232,194	3,408,963
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	7,832,117	6,809,129
Oil and natural gas properties
Property Plant And Equipment [Line Items]
Total property and equipment	208,299	201,568
Buildings
Property Plant And Equipment [Line Items]
Total property and equipment	155,992	97,029
Land
Property Plant And Equipment [Line Items]
Total property and equipment	$ 22,475	$ 22,270