Stockholders' Equity Accumulated Other Comprehensive Income (loss) - Reclassifications of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Amortization of defined benefit pension and postretirement plan items:
Total before income taxes	$ 115,290	$ 123,628	$ 112,697
Income tax benefit	(28,078)	(33,832)	(29,231)
Accumulated other comprehensive loss	(2,738)	(1,379)	1,303
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(959)	(229)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(400)	(2,453)
Other Comprehensive Income (Loss), Net of Tax	(1,359)	(2,682)
Accumulated (Gain) Loss from Commodity Contracts Cash Flows Hedges [Member]
Amortization of defined benefit pension and postretirement plan items:
Accumulated other comprehensive loss	(274)	1,092	4,571
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(1,322)	(934)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(44)	(2,545)	(4,813)
Other Comprehensive Income (Loss), Net of Tax	(1,366)	(3,479)
Accumulated (Gain) Loss from Interest Rate Swap Cash Flows Hedges
Amortization of defined benefit pension and postretirement plan items:
Accumulated other comprehensive loss	120	35	0
Other Comprehensive Income (Loss), before Reclassifications, before Tax	473	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(388)	35
Other Comprehensive Income (Loss), Net of Tax	85	35
AOCI Changes For Defined Benefit Pension And Postretirement Plans [Member]
Amortization of defined benefit pension and postretirement plan items:
Accumulated other comprehensive loss	(2,584)	(2,506)	$ (3,268)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(110)	705
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	32	57
Other Comprehensive Income (Loss), Net of Tax	$ (78)	$ 762