Risk Management and Hedging Activities - Schedule of Net Long or Short Positions Expected to be Realized (Detail)	6 Months Ended
	Jun. 30, 2020 MMBTU bbl	Jun. 30, 2019 MMBTU bbl
Crude Oil
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	(683,000)	(1,011,000)
Net (Short) Position (Bbls), Year Two | bbl	(1,422,000)	(664,000)
Net (Short) Position (Bbls), Year Three | bbl	(107,000)	(100,000)
Net (Short) Position (Bbls), Year Four | bbl	0	0
Net Long (Short) Position (Bbls), Year Five | bbl	0	0
Net (Short) Positions (Bbls), Year Six | bbl	0
Natural Gas [Member]
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One | MMBTU	(21,660,700)	(20,299,550)
Net (Short) Long Position (MMBtu), Year Two | MMBTU	(47,455,000)	(3,790,000)
Net Long Position (MMBtu), Year Three | MMBTU	(14,600,000)	0
Net Long Position (MMBtu), Year Four | MMBTU	0	0
Net Long Position (MMBtu), Year Five | MMBTU	0	0
Net Long (Short) Positions (MMBtu), year Six | MMBTU	0
Natural Gas Liquids
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	(11,981,101)	(20,528,570)
Net (Short) Position (Bbls), Year Two | bbl	(8,465,091)	(14,847,743)
Net (Short) Position (Bbls), Year Three | bbl	(1,544,842)	(5,519,594)
Net (Short) Position (Bbls), Year Four | bbl	(1,440,000)	(689)
Net Long (Short) Position (Bbls), Year Five | bbl	(1,440,000)	0
Net (Short) Positions (Bbls), Year Six | bbl	(720,000)
Natural Gas Basis Swaps
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One | MMBTU	4,450,000	2,000,000
Net (Short) Long Position (MMBtu), Year Two | MMBTU	(460,000)	3,125,000
Net Long Position (MMBtu), Year Three | MMBTU	10,037,500	(4,562,500)
Net Long Position (MMBtu), Year Four | MMBTU	10,037,500	8,212,500
Net Long Position (MMBtu), Year Five | MMBTU	7,630,000	7,300,000
Net Long (Short) Positions (MMBtu), year Six | MMBTU	905,000