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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity [Abstract]
Foreign Currency Translation, Other comprehensive (loss) income, before tax	$ (150,858)	$ 64,069	$ (85,967)	$ 144,210
Foreign Currency Translation, Income tax benefit (expense)	1	0	1	(1,086)
Foreign currency translation, Other comprehensive (loss) income, net of tax	(150,857)	64,069	(85,966)	143,124
Pension and Postretirement Benefits, Other comprehensive (loss) income, before tax	27	16	30	10
Pension and Postretirement Benefits, Income tax benefit (expense)	(4)	0	(4)	(1)
Pension and Postretirement Benefits, Other comprehensive (loss) income, net of tax	23	16	26	9
Net investment hedge, Other comprehensive (loss) income, before tax	29,864	(22,446)	11,130	(44,026)
Net investment hedge, Income tax benefit (expense)	(6,875)	8,212	(2,562)	16,107
Net investment hedge, Other comprehensive (loss) income, net of tax	22,989	(14,234)	8,568	(27,919)
Interest rate swap, Other comprehensive (loss) income, before tax	834	834	1,668	1,668
Interest rate swap, Income tax benefit (expense)	(192)	(305)	(384)	(610)
Interest rate swap, Other comprehensive (loss) income, net of tax	$ 642	$ 529	$ 1,284	$ 1,058