Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 232,982	$ 126,800	$ 187,774
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment (CTA) gain (loss)	454,269	(507,420)	(186,763)
Net investment hedge CTA gain (loss)	(235,292)	45,505	4,484
Unrealized gain (loss) on available-for-sale securities, net of tax effects of $(10), $(784) and $(4)	14	2,249	(40)
Unrealized gain (loss) on cash flow hedges, net of tax effects of $18,542, $(6,760) and $(1,840)	(54,895)	19,551	4,550
Net actuarial gain (loss) on defined benefit plans, net of tax effects of $39, $(8) and $(214)	(143)	32	1,153
Total other comprehensive income (loss), net of tax	163,953	(440,083)	(176,616)
Comprehensive income (loss), net of tax	$ 396,935	$ (313,283)	$ 11,158