Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	$ 11,678	$ 31,318	$ (18,160)	$ 104,191
AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	12,499	32,552	(15,638)	107,789
Total other comprehensive income (loss), Tax	(821)	(1,234)	(2,522)	(3,598)
Other comprehensive income (loss)	11,678	31,318	(18,160)	104,191
Cumulative translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	9,164	28,796	(25,903)	97,160
Total other comprehensive income (loss), Tax	0	0	0	0
Other comprehensive income (loss)	9,164	28,796	(25,903)	97,160
Pension and other postretirement adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	1,725	2,075	5,396	5,625
Total other comprehensive income (loss), Tax	(455)	(607)	(1,417)	(1,753)
Other comprehensive income (loss)	1,270	1,468	3,979	3,872
Reclassification adjustments for derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), Pre-tax	1,610	1,681	4,869	5,004
Total other comprehensive income (loss), Tax	(366)	(627)	(1,105)	(1,845)
Other comprehensive income (loss)	$ 1,244	$ 1,054	$ 3,764	$ 3,159