Net Property and Equipment - Schedule of Net Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Proved crude oil and natural gas properties	$ 19,520,724	$ 17,045,967
Unproved crude oil and natural gas properties	682,988	966,080
Service properties, equipment and other	307,059	274,584
Total property and equipment	20,510,771	18,286,631
Accumulated depreciation, depletion and amortization	(6,447,443)	(4,650,779)
Net property and equipment	$ 14,063,328	$ 13,635,852