Risk Management and Derivative Instruments - Unrealized and Realized Gains and Losses Related to Derivative Instruments (Detail) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	May 04, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments Gain Loss [Line Items]
(Gain) loss on commodity derivative instruments		$ 31,609	$ 6,700	$ (8,155)
Interest expense, net		(15,936)	(16,855)	(21,923)
Predecessor [Member]
Derivative Instruments Gain Loss [Line Items]
(Gain) loss on commodity derivative instruments	$ (23,076)
Interest expense, net	(10,243)
Commodity derivatives [Member]
Derivative Instruments Gain Loss [Line Items]
(Gain) loss on commodity derivative instruments		31,609	6,700	(8,155)
Commodity derivatives [Member] | Predecessor [Member]
Derivative Instruments Gain Loss [Line Items]
(Gain) loss on commodity derivative instruments	(23,076)
Interest rate derivatives [Member]
Derivative Instruments Gain Loss [Line Items]
Interest expense, net		$ 0	$ (224)	$ 0
Interest rate derivatives [Member] | Predecessor [Member]
Derivative Instruments Gain Loss [Line Items]
Interest expense, net	$ 0