Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Before Tax		$ (174,347)	$ 319,059	$ (115,429)
Other Comprehensive Income (Loss), Income Tax		37,510	(90,923)	37,235
Other Comprehensive Income (Loss), Net of Tax		(136,837)	228,136	(78,194)
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax			33,175
Other Comprehensive Income (Loss) before Reclassifications, Tax			0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(35,584)	33,175
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax			137
Reclassification from AOCI, Current Period, Tax			0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	137
Other Comprehensive Income (Loss), Before Tax		(35,584)	33,312	(22,149)
Other Comprehensive Income (Loss), Income Tax		0	0	0
Other Comprehensive Income (Loss), Net of Tax		(35,584)	33,312	(22,149)
Unrealized Gains (Losses) on Available- for- Sale Securities [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax				55,507
Other Comprehensive Income (Loss) before Reclassifications, Tax				(22,203)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0	67,252	33,304
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax				1,879
Reclassification from AOCI, Current Period, Tax				(752)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	0	1,127
Other Comprehensive Income (Loss), Before Tax			112,086	57,386
Other Comprehensive Income (Loss), Income Tax			(44,834)	(22,955)
Other Comprehensive Income (Loss), Net of Tax		0	67,252	34,431
Pension and Other Postretirement Plans [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(70,629)	131,108
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(42,563)	(6,050)	(16,417)
Reclassification from AOCI, Current Period, Tax		11,492	2,421	6,567
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(31,071)	(3,629)	(9,850)
Other Comprehensive Income (Loss), Before Tax		(139,314)	173,549	(150,332)
Other Comprehensive Income (Loss), Income Tax		37,614	(46,070)	60,133
Other Comprehensive Income (Loss), Net of Tax		(101,700)	127,479	(90,199)
Net Actuarial Loss [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		(101,013)	179,674	(133,915)
Other Comprehensive Income (Loss) before Reclassifications, Tax		27,273	(48,511)	53,566
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(73,740)	131,163	(80,349)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(11,349)	(6,527)	1,157
Reclassification from AOCI, Current Period, Tax		3,064	2,612	(463)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(8,285)	(3,915)	694
Net Prior Service Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		4,262	(75)
Other Comprehensive Income (Loss) before Reclassifications, Tax		(1,151)	20
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		3,111	(55)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(947)	477	419
Reclassification from AOCI, Current Period, Tax		256	(191)	(167)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(691)	286	252
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]	(30,267)	0	(17,993)
Reclassification from AOCI, Current Period, Tax		8,172		7,197
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(22,095)		(10,796)
Cash Flow Hedge
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		579	(29)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(132)	122
Other Comprehensive Income (Loss), Before Tax		551	112	(334)
Other Comprehensive Income (Loss), Income Tax		(104)	(19)	57
Other Comprehensive Income (Loss), Net of Tax		$ 447	$ 93	$ (277)

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension and postretirement plan cost (see Note 14) and are included in non-operating pension and postretirement benefit income in the Company’s Consolidated Statements of Operations.