Derivative Instruments - Outstanding Commodity Derivatives (Details) - Natural gas (NYMEX)	1 Months Ended	9 Months Ended
	Oct. 30, 2020 MMBTU $ / MMBTU	Sep. 30, 2020 MMBTU $ / MMBTU
Derivative [Line Items]
Volume (in Mmbtu) | MMBTU		9,300,000
Swaps Weighted-Average (in usd per Mmbtu)		2.25
Volume (in Mmbtu) | MMBTU		15,500,000
Floor, Weighted-Average (in usd per Mmbtu)		2.05
Ceiling, Weighted-Average (in usd per Mmbtu)		2.24
Minimum
Derivative [Line Items]
Derivative, Floor Price		1.90
Derivative, Cap Price		2.10
Maximum
Derivative [Line Items]
Derivative, Floor Price		2.15
Derivative, Cap Price		2.38
Volume (in Mmbtu) | MMBTU		18,250,000
Swaps Weighted-Average (in usd per Mmbtu)		2.74
Volume (in Mmbtu) | MMBTU		127,750,000
Floor, Weighted-Average (in usd per Mmbtu)		2.64
Ceiling, Weighted-Average (in usd per Mmbtu)		3.02
Minimum
Derivative [Line Items]
Derivative, Floor Price		2.50
Derivative, Cap Price		2.83
Maximum
Derivative [Line Items]
Derivative, Floor Price		2.80
Derivative, Cap Price		3.50
Volume (in Mmbtu) | MMBTU		10,700,000
Floor, Weighted-Average (in usd per Mmbtu)		2.50
Ceiling, Weighted-Average (in usd per Mmbtu)		2.80
Subsequent event
Derivative [Line Items]
Volume (in Mmbtu) | MMBTU	36,500,000
Floor, Weighted-Average (in usd per Mmbtu)	2.83
Ceiling, Weighted-Average (in usd per Mmbtu)	3.32
Minimum | Subsequent event
Derivative [Line Items]
Derivative, Floor Price	2.80
Derivative, Cap Price	3.00
Maximum | Subsequent event
Derivative [Line Items]
Derivative, Floor Price	2.85
Derivative, Cap Price	3.94