Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Provision for Income Taxes	$ 18,292	$ 9,734
Effective Income Tax Rate Reconciliation, Percent	16.00%	56.00%
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount	$ (22,957)
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Percent	20.00%
Increase (Decrease) in Deferred Tax Assets, Changes in Unrealized Gain (Loss) on Marketable Securities	$ 21	$ (8)
Increase (Decrease) in Deferred Tax Assets, Changes in Foreign Currency Translation Adjustments	$ (140)	$ 1,183