Derivative Instruments - Financial Instruments for Hedging Volume (Detail)	Sep. 30, 2019 MMBTU $ / unit bbl
Interest Rate Swap,October - December 2019 | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	1,537,519
Weighted Average Price (usd per unit)	59.01
Interest Rate Swap,October - December 2019 | Natural Gas (MMbtu)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed natural gas volume | MMBTU	644,000
Weighted Average Price (usd per unit)	2.11
Interest Rate Swap,Year 2020 | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	4,986,500
Weighted Average Price (usd per unit)	58.86
Interest Rate Swap,Year 2020 | Natural Gas (MMbtu)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed natural gas volume | MMBTU	0
Weighted Average Price (usd per unit)	0
Interest Rate Swap,Year 2021 | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	181,000
Weighted Average Price (usd per unit)	57.13
Interest Rate Swap,Year 2021 | Natural Gas (MMbtu)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed natural gas volume | MMBTU	0
Weighted Average Price (usd per unit)	0
October – December 2019 | Cashless Collars | Oil (Bbls)
Derivative Instruments, Gain (Loss) [Line Items]
Hedge backed oil volume | bbl	276,000
Weighted Average Floor Price (usd per unit)	55.00
Weighted Average Ceiling Price (usd per unit)	77.56