Accumulated Other Comprehensive Income (AOCI) (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 507,523
Ending balance	538,060
Translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(133,298)	$ (108,655)
Other comprehensive income/(loss) before reclassifications	28,453	2,393
Pension/postretirement plan remeasurement
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	28,453	2,393
Ending balance	(104,845)	(106,262)
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	(1,079)	12
Pension/postretirement plan remeasurement		105
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	332	244
Net current period other comprehensive income	(747)	361
Ending balance	(52,466)	(48,364)
Derivative valuation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	828	(1,464)
Other comprehensive income/(loss) before reclassifications	(619)	(4,608)
Pension/postretirement plan remeasurement
Interest expense related to swaps reclassified to the Statement of Income, net of tax	585	363
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax
Net current period other comprehensive income	(34)	(4,245)
Ending balance	794	(5,709)
Total Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(184,189)	(158,844)
Other comprehensive income/(loss) before reclassifications	26,755	(2,203)
Pension/postretirement plan remeasurement		105
Interest expense related to swaps reclassified to the Statement of Income, net of tax	585	363
Pension and postretirement liability adjustments reclassified to Statement of Income, net of tax	332	244
Net current period other comprehensive income	27,672	(1,491)
Ending balance	$ (156,517)	$ (160,335)