Derivative Instruments - Financial Instruments for Hedging Volume (Detail)	Mar. 31, 2019 MMBTU $ / unit bbl
April – December 2019 | Swap contracts | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	4,646,533
Weighted Average Price (usd per unit)	59.07
April – December 2019 | Swap contracts | Natural Gas (MMbtu)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed natural gas volume | MMBTU	1,925,000
Weighted Average Price (usd per unit)	2.11
April – December 2019 | Cashless Collars | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	552,000
Weighted Average Floor Price (usd per unit)	55.00
Weighted Average Ceiling Price (usd per unit)	77.56
For the year 2020 | Swap contracts | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	4,024,000
Weighted Average Price (usd per unit)	59.42
For the year 2020 | Swap contracts | Natural Gas (MMbtu)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed natural gas volume | MMBTU	0
Weighted Average Price (usd per unit)	0.00