Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details 3) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense		$ 17,165	$ 9,035	$ 25,236	$ 17,164
Provision for Income Taxes		16,100	23,900	29,700	26,600
Net of Tax		(46,635)	(41,999)	(89,600)	(63,085)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net of Tax		(2,391)	(836)	(3,332)	(1,833)
Foreign Currency Translation Adjustment [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax				0
Unrealized Gain on Available-for-Sale Securities [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax				0
Pension and Other Postretirement Plans [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax		(3,224)	(1,448)	(4,515)	(3,151)
Provision for Income Tax		869	579	1,217	1,260
Reclassifications, net of tax		(2,355)	(869)	(3,298)	(1,891)
Net Prior Service Cost [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]	70	120	146	240
Provision for Income Tax		(19)	(48)	(40)	(96)
Reclassifications, net of tax		51	72	106	144
Net Actuarial (Gain) Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, before tax	[1]	(3,294)	(1,568)	(4,661)	(3,391)
Provision for Income Tax		888	627	1,257	1,356
Reclassifications, net of tax		(2,406)	(941)	(3,404)	(2,035)
Cash Flow Hedge [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax				(34)
Cash Flow Hedge [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense		(45)	41	(42)	72
Provision for Income Taxes		9	(8)	8	(14)
Net of Tax		$ (36)	$ 33	$ (34)	$ 58

[1] These accumulated other comprehensive income components are components of net periodic pension and postretirement plan cost (see Note 12) and are included in non-operating pension and postretirement benefit income in the Company’s Condensed Consolidated Statements of Operations.