Derivative Instruments - Outstanding Derivative Contracts (Details) - Natural Gas Costless Collars	9 Months Ended
	Sep. 30, 2020 MMBTU $ / MMBTU
2020
Derivative [Line Items]
Notional volume (MMBtu) | MMBTU	4,600,000
Weighted average floor price ($/MMBtu)	2.31
Weighted average ceiling price ($/MMBtu)	3.00
2021
Derivative [Line Items]
Notional volume (MMBtu) | MMBTU	12,150,000
Weighted average floor price ($/MMBtu)	2.31
Weighted average ceiling price ($/MMBtu)	3.00