Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 124,009	$ 105,064	$ 126,673
Other comprehensive income, net of taxes:
Change in cumulative translation adjustment	(56,704)	(71,406)	9,975
Change in unrealized gain (loss) on available-for-sale securities	40	(27)	(15)
Change in minimum pension liability	189	(246)	267
Changes due to cash flow hedging instruments:
Net loss on hedge instruments	(8,078)	(11,050)	(2,492)
Reclassification to net income of previously deferred losses related to hedge derivatives instruments	11,025	8,090	837
Comprehensive income	$ 70,481	$ 30,425	$ 135,245