Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Provision for Income Taxes	$ 7,821	$ 4,938
Effective Income Tax Rate Reconciliation, Percent	9.00%	4.00%
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount	$ 12,161	$ 21,864
Effective Income Tax Rate Reconciliation, ASU 2016-09 Benefit for Stock Compensation, Percent	14.00%	19.00%
Increase (Decrease) In Deferred Tax Assets Associated With Changes In Unrealized Gain Loss On Marketable Securities In Accumulated Other Comprehensive Income Loss	$ 185	$ 166
Increase (Decrease) In Deferred Tax Assets Associated With Changes In Foreign Currency Translation Adjustment Gain Loss In Accumulated Other Comprehensive Income Loss	$ (890)	$ (1,095)