Fair Value Measurements - Property Impairments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property impairments	$ 81,469	$ 0	$ 82,340	$ 0
Unproved property impairments	41,847	66,112	92,349	145,039
Oil and gas property fair value after impairment	72,000		72,000
Property impairments	123,316	$ 66,112	174,689	$ 145,039
Arkoma Woodford [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property impairments	81,200		81,200
Non-core [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property impairments	$ 300		$ 1,100