Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit risk valuation adjustment	$ 400	$ 200
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	45,308	311
Total commodity derivative liabilities	(1,169)	(7,732)
Recurring | Non-trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	44,622	203
Total commodity derivative liabilities	(77)	(7,660)
Recurring | Trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	686	108
Total commodity derivative liabilities	(1,092)	(72)
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	1,107	104
Total commodity derivative liabilities	0	(5)
Recurring | Level 1 | Non-trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	1,079	104
Total commodity derivative liabilities	0	(5)
Recurring | Level 1 | Trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	28	0
Total commodity derivative liabilities	0	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	44,201	207
Total commodity derivative liabilities	(1,169)	(7,727)
Recurring | Level 2 | Non-trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	43,543	99
Total commodity derivative liabilities	(77)	(7,655)
Recurring | Level 2 | Trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	658	108
Total commodity derivative liabilities	(1,092)	(72)
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	0	0
Total commodity derivative liabilities	0	0
Recurring | Level 3 | Non-trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	0	0
Total commodity derivative liabilities	0	0
Recurring | Level 3 | Trading commodity derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total commodity derivative assets	0	0
Total commodity derivative liabilities	$ 0	$ 0