Accumulated Other Comprehensive (Loss) Income - Amount of Income Tax Benefit (Expense) Allocated to Component of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Equity [Abstract]
Foreign Currency Translation, Other comprehensive income (loss), before tax	$ 64,891	$ 80,141
Foreign Currency Translation, Income tax benefit (expense)	0	(1,086)
Foreign currency translation, Other comprehensive income (loss), net of tax	64,891	79,055
Pension and Postretirement Benefits, Other comprehensive income (loss), before tax	3	(6)
Pension and Postretirement Benefits, Income tax benefit (expense)	0	(1)
Pension and Postretirement Benefits, Other comprehensive income (loss), net of tax	3	(7)
Net investment hedge, Other comprehensive income (loss), before tax	(18,734)	(21,580)
Net investment hedge, Income tax benefit (expense)	4,313	7,895
Net investment hedge, Other comprehensive income (loss), net of tax	(14,421)	(13,685)
Interest rate swap, Other comprehensive income (loss), before tax	834	834
Interest rate swap, Income tax benefit (expense)	(192)	(305)
Interest rate swap, Other comprehensive income (loss), net of tax	$ 642	$ 529