Other Comprehensive Income (Loss) - (Components of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Cumulative translation adjustment, Pre-tax	$ 110,421	$ (76,822)	$ (63,441)
Cumulative translation adjustment, Tax	0	0	0
Cumulative translation adjustment, Net of Tax	110,421	(76,822)	(63,441)
Reclassification of foreign currency translation to earnings upon sale of business, Pre-tax	2,749	14,257	(4,725)
Reclassification of foreign currency translation to earnings upon sale of business, Tax	0	0	0
Reclassification of foreign currency translation to earnings upon sale of business, Net of Tax	2,749	14,257	(4,725)
Tax effect of reversal of indefinite assertion on certain intercompany loans, Pre-tax	(3,932)	0
Tax effect of reversal of indefinite assertion on certain intercompany loans, Tax	0	0
Tax effect of reversal of indefinite assertion on certain intercompany loans, Net of Tax	(3,932)	0	0
Foreign currency translation adjustments, Pre-tax	109,238	(62,565)
Foreign currency translation adjustments, Tax	0	0
Foreign currency translation adjustments, net of tax	109,238	(62,565)
Pension and other postretirement adjustments
Net gain (loss) arising during the year, Pre-tax	(5,355)	(1,927)	8,318
Net gain (loss) arising during the year, Tax	828	789	(2,411)
Net gain (loss) arising during the year, Net of Tax	(4,527)	(1,138)	5,907
Amortization/recognition of settlement loss, Pre-tax	3,814	7,083	4,939
Amortization/recognition of settlement loss, Tax	(589)	(2,896)	(1,431)
Amortization/recognition of settlement loss, Net of Tax	3,225	4,187	3,508
Pension and other postretirement adjustments, Pre-tax	(1,541)	5,156	13,257
Pension and other postretirement adjustments, Tax	239	(2,107)	(3,842)
Pension and other postretirement adjustments, Net of Tax	(1,302)	3,049	9,415
Reclassification adjustments for derivatives, Pre-tax	6,655	6,851	7,030
Reclassification adjustments for derivatives, Tax	(2,445)	(2,490)	(2,499)
Reclassification adjustments for derivatives, Net of tax	4,210	4,361	4,531
Total other comprehensive income (loss), Pre-tax	114,352	(50,558)	(47,879)
Total other comprehensive income (loss), Tax	(2,206)	(4,597)	(6,341)
Other comprehensive income (loss)	$ 112,146	$ (55,155)	$ (54,220)