Accumulated Other Comprehensive Income (AOCI) (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 507,523
Ending balance	560,668
Translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(133,298)	$ (108,655)
Other comprehensive income/(loss) before reclassifications	40,775	2,216
Interest expense related to swaps reclassified to the Statement of Income, net of tax
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax
Net current period other comprehensive income	40,775	2,216
Ending balance	(92,523)	(106,439)
Pension and postretirement liability adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(51,719)	(48,725)
Other comprehensive income/(loss) before reclassifications	(1,427)	330
Interest expense related to swaps reclassified to the Statement of Income, net of tax
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax	498	372
Net current period other comprehensive income	(929)	702
Ending balance	(52,648)	(48,023)
Derivative valuation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	828	(1,464)
Other comprehensive income/(loss) before reclassifications	(679)	(4,300)
Interest expense related to swaps reclassified to the Statement of Income, net of tax	768	1,045
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax
Net current period other comprehensive income	89	(3,255)
Ending balance	917	(4,719)
Total Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(184,189)	(158,844)
Other comprehensive income/(loss) before reclassifications	38,669	(1,754)
Interest expense related to swaps reclassified to the Statement of Income, net of tax	768	1,045
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax	498	372
Net current period other comprehensive income	39,935	(337)
Ending balance	$ (144,254)	$ (159,181)