Derivative Accounting - Derivative Instruments in the Balance Sheets (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Assets
Gross recognized derivatives	$ 25,138,000	$ 132,229,000
Liabilities
Amount Reported on Balance Sheets	(99,137,000)	(42,446,000)
Commodity Contracts
Assets
Gross recognized derivatives	43,733,000	153,261,000
Amounts offset	(19,004,000)	(21,191,000)
Net Recognized Derivatives	24,729,000	132,070,000
Other	0	28,000
Amount Reported on Balance Sheets	24,729,000	132,098,000
Liabilities
Gross recognized derivatives	(110,921,000)	(56,893,000)
Amounts offset	19,004,000	21,191,000
Net Recognized Derivatives	(91,917,000)	(35,702,000)
Other	(6,271,000)	(5,835,000)
Amount Reported on Balance Sheets	(98,188,000)	(41,537,000)
Assets and Liabilities
Gross recognized derivatives	(67,188,000)	96,368,000
Amounts offset	0	0
Net Recognized Derivatives	(67,188,000)	96,368,000
Other	(6,271,000)	(5,807,000)
Amount Reported on Balance Sheets	(73,459,000)	90,561,000
Cash collateral received subject to offsetting	0
Cash collateral received from counterparties	6,271,000	5,835,000
Commodity Contracts | Current assets
Assets
Gross recognized derivatives	22,876,000	103,484,000
Amounts offset	(11,180,000)	(15,808,000)
Net Recognized Derivatives	11,696,000	87,676,000
Other	0	28,000
Amount Reported on Balance Sheets	11,696,000	87,704,000
Commodity Contracts | Investments and other assets
Assets
Gross recognized derivatives	20,857,000	49,777,000
Amounts offset	(7,824,000)	(5,383,000)
Net Recognized Derivatives	13,033,000	44,394,000
Other	0	0
Amount Reported on Balance Sheets	13,033,000	44,394,000
Commodity Contracts | Current liabilities
Liabilities
Gross recognized derivatives	(78,742,000)	(47,670,000)
Amounts offset	11,180,000	15,808,000
Net Recognized Derivatives	(67,562,000)	(31,862,000)
Other	(6,271,000)	(5,835,000)
Amount Reported on Balance Sheets	(73,833,000)	(37,697,000)
Assets and Liabilities
Cash collateral received from counterparties	6,271,000	5,835,000
Commodity Contracts | Deferred credits and other
Liabilities
Gross recognized derivatives	(32,179,000)	(9,223,000)
Amounts offset	7,824,000	5,383,000
Net Recognized Derivatives	(24,355,000)	(3,840,000)
Other	0	0
Amount Reported on Balance Sheets	(24,355,000)	(3,840,000)
Assets and Liabilities
Cash collateral received from counterparties	$ 0	$ 0