Stockholders' Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustments, net of tax	$ (307,332)	$ (284,767)
Net unrealized gain (loss) on available for sale securities, net of tax	220	(127)
Accumulated other comprehensive income (loss)	(307,112)	(284,894)
2.5% Senior Notes Due 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation losses, net of tax	13,000	1,000
Foreign currency translation losses, before tax	$ 21,000	$ 2,000
Debt, interest rate (percentage)	2.50%	2.50%