Derivative Accounting - Derivative Instruments in the Balance Sheets (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Assets
Gross Recognized Derivatives	$ 251,658,000	$ 110,389,000
Liabilities
Gross Recognized Derivatives	(4,298,000)
Amount Reported on Balance Sheets	(7,861,000)	(4,373,000)
Commodity Contracts
Assets
Gross Recognized Derivatives	262,753,000	115,079,000
Amounts Offset	(11,113,000)	(4,740,000)
Net Recognized Derivatives	251,640,000	110,339,000
Other	18,000	50,000
Amount Reported on Balance Sheets	251,658,000	110,389,000
Liabilities
Gross Recognized Derivatives	(3,564,000)	(7,478,000)
Amounts Offset	2,313,000	4,740,000
Net Recognized Derivatives	(1,251,000)	(2,738,000)
Other	(6,610,000)	(1,635,000)
Amount Reported on Balance Sheets	(7,861,000)	(4,373,000)
Assets and Liabilities
Gross Recognized Derivatives	259,189,000	107,601,000
Amounts Offset	(8,800,000)	0
Net Recognized Derivatives	250,389,000	107,601,000
Other	(6,592,000)	(1,585,000)
Amount Reported on Balance Sheets	243,797,000	106,016,000
Cash collateral received subject to offsetting	8,800,000
Cash collateral received from counterparties	6,610,000	1,635,000
Commodity Contracts | Current assets
Assets
Gross Recognized Derivatives	175,362,000	66,777,000
Amounts Offset	(10,586,000)	(3,346,000)
Net Recognized Derivatives	164,776,000	63,431,000
Other	18,000	50,000
Amount Reported on Balance Sheets	164,794,000	63,481,000
Commodity Contracts | Investments and other assets
Assets
Gross Recognized Derivatives	87,391,000	48,302,000
Amounts Offset	(527,000)	(1,394,000)
Net Recognized Derivatives	86,864,000	46,908,000
Other	0	0
Amount Reported on Balance Sheets	86,864,000	46,908,000
Commodity Contracts | Current liabilities
Liabilities
Gross Recognized Derivatives	(2,416,000)	(6,084,000)
Amounts Offset	1,786,000	3,346,000
Net Recognized Derivatives	(630,000)	(2,738,000)
Other	(6,610,000)	(1,635,000)
Amount Reported on Balance Sheets	(7,240,000)	(4,373,000)
Assets and Liabilities
Cash collateral received from counterparties	6,610,000	1,635,000
Commodity Contracts | Deferred credits and other
Liabilities
Gross Recognized Derivatives	(1,148,000)	(1,394,000)
Amounts Offset	527,000	1,394,000
Net Recognized Derivatives	(621,000)	0
Other	0	0
Amount Reported on Balance Sheets	(621,000)	0
Assets and Liabilities
Cash collateral received from counterparties	$ 0	$ 0