Net Property and Equipment - Schedule of Net Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Capital Expenditures	$ 1,100,000
Property, Plant and Equipment, Disposals	804,000
Unproved property impairments	234,397	$ 263,253	$ 292,586
Proved crude oil and natural gas properties	19,802,395	19,520,724
Unproved crude oil and natural gas properties	429,562	682,988
Service properties, equipment and other	301,788	307,059
Total property and equipment	20,533,745	20,510,771
Accumulated depreciation, depletion and amortization	(7,652,518)	(6,447,443)
Net property and equipment	$ 12,881,227	$ 14,063,328	$ 14,063,328