Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Before Tax		$ 366,561	$ (838,641)	$ 501,454
Other Comprehensive Income (Loss), Income Tax		(88,375)	203,404	(133,380)
Other Comprehensive Income (Loss), Net of Tax		278,186	(635,237)	368,074
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		21,927	(48,340)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	0
Other Comprehensive Income (Loss), Before Tax		21,927	(48,340)	(16,052)
Other Comprehensive Income (Loss), Income Tax		0	0	0
Other Comprehensive Income (Loss), Net of Tax		21,927	(48,340)	(16,052)
Pension and Other Postretirement Plans [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		291,537	(540,079)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(41,592)	(67,969)	(2,436)
Reclassification from AOCI, Current Period, Tax		10,649	17,482	627
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(30,943)	(50,487)	(1,809)
Other Comprehensive Income (Loss), Before Tax		350,264	(795,066)	517,157
Other Comprehensive Income (Loss), Income Tax		(89,670)	204,500	(133,287)
Other Comprehensive Income (Loss), Net of Tax		260,594	(590,566)	383,870
Net Actuarial Loss [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		380,593	(727,097)	519,595
Other Comprehensive Income (Loss) before Reclassifications, Tax		(97,436)	187,018	(133,915)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		283,157	(540,079)	385,680
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(42,146)	(70,833)	(5,486)
Reclassification from AOCI, Current Period, Tax		10,790	18,219	1,414
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(31,356)	(52,614)	(4,072)
Net Prior Service Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		11,263		(2)
Other Comprehensive Income (Loss) before Reclassifications, Tax		(2,883)		1
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		8,380		(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	1,641	2,864	3,170
Reclassification from AOCI, Current Period, Tax		(420)	(737)	(817)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		1,221	2,127	2,353
Curtailments and settlements Included in Net Income [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(1,087)	0	(120)
Reclassification from AOCI, Current Period, Tax		279		30
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(808)		(90)
Cash Flow Hedges
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		1,028	3,276
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(5,363)	393
Other Comprehensive Income (Loss), Before Tax		(5,630)	4,765	349
Other Comprehensive Income (Loss), Income Tax		1,295	(1,096)	(93)
Other Comprehensive Income (Loss), Net of Tax		$ (4,335)	$ 3,669	$ 256

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension and postretirement plan cost (see Note 15) and are included in non-operating pension and postretirement benefit income in the Company’s Consolidated Statements of Operations.