Accumulated Other Comprehensive Loss (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss)
Beginning balance	$ 60,653	$ 112,632	$ 70,621
Other comprehensive income (loss) before reclassifications	(22,165)	(85,999)	18,857
Amounts reclassified from accumulated other comprehensive loss	6,484	30,747	39,962
Other comprehensive (loss) income, net of tax	(15,681)	(55,252)	58,819
Ending balance	(368,576)	60,653	112,632
Cash flow hedges
Accumulated Other Comprehensive Income (Loss)
Beginning balance	12,503	3,803	(1,411)
Other comprehensive income (loss) before reclassifications	1,715	9,246	5,069
Amounts reclassified from accumulated other comprehensive loss	(7,256)	(546)	145
Other comprehensive (loss) income, net of tax	(5,541)	8,700	5,214
Ending balance	6,962	12,503	3,803
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(39,440)	(6,249)	402
Other comprehensive income (loss) before reclassifications	5,969	(33,198)	(6,662)
Amounts reclassified from accumulated other comprehensive loss	8	7	11
Other comprehensive (loss) income, net of tax	5,977	(33,191)	(6,651)
Ending balance	(33,463)	(39,440)	(6,249)
Pension and postretirement benefit plans
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(716,056)	(756,639)	(851,063)
Other comprehensive income (loss) before reclassifications	(55,128)	9,297	54,618
Amounts reclassified from accumulated other comprehensive loss	13,732	31,286	39,806
Other comprehensive (loss) income, net of tax	(41,396)	40,583	94,424
Ending balance	(757,452)	(716,056)	(756,639)
Foreign currency adjustments
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(92,571)	(21,227)	12,941
Other comprehensive income (loss) before reclassifications	25,279	(71,344)	(34,168)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive (loss) income, net of tax	25,279	(71,344)	(34,168)
Ending balance	(67,292)	(92,571)	(21,227)
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(835,564)	(780,312)	(839,131)
Other comprehensive (loss) income, net of tax	(15,681)	(55,252)	58,819
Ending balance	$ (851,245)	$ (835,564)	$ (780,312)