Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	$ 30,252	$ 23,216
AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	31,128	24,403
Total other comprehensive income (loss), Tax	(876)	(1,187)
Other comprehensive income (loss)	30,252	23,216
Cumulative translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	27,578	21,050
Total other comprehensive income (loss), Tax	0	0
Other comprehensive income (loss)	27,578	21,050
Pension and other postretirement adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	1,918	1,676
Total other comprehensive income (loss), Tax	(505)	(552)
Other comprehensive income (loss)	1,413	1,124
Reclassification adjustments for derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	1,632	1,677
Total other comprehensive income (loss), Tax	(371)	(635)
Other comprehensive income (loss)	$ 1,261	$ 1,042