Accumulated Other Comprehensive Loss (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss)
Beginning balance	$ (368,576)	$ 60,653	$ 112,632
Other comprehensive income (loss) before reclassifications	(72,130)	(22,165)	(85,999)
Amounts reclassified from accumulated other comprehensive loss	84,204	6,484	30,747
Other comprehensive income (loss), net of tax	12,074	(15,681)	(55,252)
Ending balance	(578,433)	(368,576)	60,653
Cash flow hedges
Accumulated Other Comprehensive Income (Loss)
Beginning balance	6,962	12,503	3,803
Other comprehensive income (loss) before reclassifications	631	1,715	9,246
Amounts reclassified from accumulated other comprehensive loss	(7,593)	(7,256)	(546)
Other comprehensive income (loss), net of tax	(6,962)	(5,541)	8,700
Ending balance	0	6,962	12,503
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(33,463)	(39,440)	(6,249)
Other comprehensive income (loss) before reclassifications	228	5,969	(33,198)
Amounts reclassified from accumulated other comprehensive loss	3,638	8	7
Other comprehensive income (loss), net of tax	3,866	5,977	(33,191)
Ending balance	(29,597)	(33,463)	(39,440)
Pension and postretirement benefit plans
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(757,452)	(716,056)	(756,639)
Other comprehensive income (loss) before reclassifications	(35,525)	(55,128)	9,297
Amounts reclassified from accumulated other comprehensive loss	88,159	13,732	31,286
Other comprehensive income (loss), net of tax	52,634	(41,396)	40,583
Ending balance	(704,818)	(757,452)	(716,056)
Foreign currency adjustments
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(67,292)	(92,571)	(21,227)
Other comprehensive income (loss) before reclassifications	(37,464)	25,279	(71,344)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive income (loss), net of tax	(37,464)	25,279	(71,344)
Ending balance	(104,756)	(67,292)	(92,571)
Total
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(851,245)	(835,564)	(780,312)
Other comprehensive income (loss), net of tax	12,074	(15,681)	(55,252)
Ending balance	$ (839,171)	$ (851,245)	$ (835,564)