Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details 3) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net		$ 12,559	$ (3,142)	$ (2,333)	$ (9,187)	$ 2,640	$ (1,963)	$ (4,069)	$ (849)	$ (2,103)	$ (4,241)	$ 12,642
Interest expense		6,531	6,135	17,165	8,071	8,103	8,619	9,035	8,129	37,902	33,886	35,390
Provision for (Benefit from) Income Taxes		12,400	10,000	16,100	13,600	(159,700)	13,400	23,900	2,700	52,100	(119,700)	81,200
Net of Tax		$ (56,738)	$ (125,070)	$ (46,635)	$ (42,965)	$ (214,560)	$ (24,844)	$ (41,999)	$ (21,086)	(271,408)	(302,489)	(169,458)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net of Tax										(31,203)	(3,370)	(8,710)
Foreign Currency Translation Adjustments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax											137
Provision for income taxes											0
Reclassifications, net of tax										0	137
Foreign Currency Translation Adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net										0	137	0
Unrealized Gains (Losses) on Available- for- Sale Securities [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax												1,879
Provision for income taxes												(752)
Reclassifications, net of tax										0	0	1,127
Unrealized Gains (Losses) on Available- for- Sale Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net										0	0	1,879
Provision for (Benefit from) Income Taxes										0	0	(752)
Net of Tax										0	0	1,127
Pension and Other Postretirement Plans [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax										(42,563)	(6,050)	(16,417)
Provision for income taxes										11,492	2,421	6,567
Reclassifications, net of tax										(31,071)	(3,629)	(9,850)
Net Actuarial Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]									(11,349)	(6,527)	1,157
Provision for income taxes										3,064	2,612	(463)
Reclassifications, net of tax										(8,285)	(3,915)	694
Net Prior Service Cost [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]									(947)	477	419
Provision for income taxes										256	(191)	(167)
Reclassifications, net of tax										(691)	286	252
Curtailment (Gains) Losses Included in Net Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]									(30,267)	0	(17,993)
Provision for income taxes										8,172		7,197
Reclassifications, net of tax										(22,095)		(10,796)
Cash Flow Hedge
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax										(132)	122
Cash Flow Hedge | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense										(163)	152	16
Provision for (Benefit from) Income Taxes										31	(30)	(3)
Net of Tax										$ (132)	$ 122	$ 13

[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.