Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended		3 Months Ended			9 Months Ended
	Mar. 31, 2020 $ / unit	Dec. 31, 2019 USD ($) $ / unit	Sep. 30, 2020 USD ($) $ / unit bbl	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) $ / unit bbl	Sep. 30, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Principal | $		$ 765,000,000	$ 765,000,000			$ 765,000,000
Accounts Receivable, Due from One Joint Interest Partner | $			6,300,000			6,300,000
Accounts Receivable, Due from One Joint Interest Partner, Noncurrent | $			10,000,000.0			$ 10,000,000.0
Reverse stock split ratio						0.02
8.75% Senior Notes
Property, Plant and Equipment [Line Items]
Principal | $		$ 275,000,000	275,000,000			$ 275,000,000
Senior Notes [Member]
Property, Plant and Equipment [Line Items]
Principal | $			$ 625,000,000.0			$ 625,000,000.0
Oil (Bbls)
Property, Plant and Equipment [Line Items]
Crude oil price (per barrel)	30.45	59.80
Oil (Bbls) | Derivative, Swap Type | October – December 2020
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			1,311,000			1,311,000
Weighted Average Price (usd per unit)			56.29			56.29
Oil (Bbls) | Derivative, Swap Type | For the year 2021
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			3,098,000			3,098,000
Weighted Average Price (usd per unit)			54.30			54.30
Oil (Bbls) | Derivative, Swap Type | For the year 2022
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			0			0
Weighted Average Price (usd per unit)			0			0
Oil (Bbls) | Derivative, Roll Swaps | October – December 2020
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			138,000			138,000
Weighted Average Price (usd per unit)			(1.47)			(1.47)
Oil (Bbls) | Derivative, Roll Swaps | For the year 2021
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			182,500			182,500
Weighted Average Price (usd per unit)			(0.25)			(0.25)
Oil (Bbls) | Derivative, Roll Swaps | For the year 2022
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			0			0
Weighted Average Price (usd per unit)			0			0
Oil (Bbls) | Swaption | October – December 2020
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			0			0
Weighted Average Price (usd per unit)			0			0
Oil (Bbls) | Swaption | For the year 2021
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			0			0
Weighted Average Price (usd per unit)			0			0
Oil (Bbls) | Swaption | For the year 2022
Property, Plant and Equipment [Line Items]
Hedge backed oil volume | bbl			1,092,000			1,092,000
Weighted Average Price (usd per unit)			55.08			55.08
Natural Gas (MMbtu) | Derivative, Swap Type | October – December 2020
Property, Plant and Equipment [Line Items]
Hedge Backed Gas Volume | bbl			1,840,000			1,840,000
Weighted Average Price (usd per unit)			1.83			1.83
Natural Gas (MMbtu) | Derivative, Swap Type | For the year 2021
Property, Plant and Equipment [Line Items]
Hedge Backed Gas Volume | bbl			5,790,000			5,790,000
Weighted Average Price (usd per unit)			2.13			2.13
Natural Gas (MMbtu) | Derivative, Swap Type | For the year 2022
Property, Plant and Equipment [Line Items]
Hedge Backed Gas Volume | bbl			3,650,000			3,650,000
Weighted Average Price (usd per unit)			2.13			2.13
Proved Oil and Gas Properties
Property, Plant and Equipment [Line Items]
Impairment of Oil and Gas Properties | $			$ 0	$ 1,200,000,000	$ 0	$ 1,188,566,000	$ 0