CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Common Stock Restricted Stock	Common Stock Restricted Stock Units (RSUs)	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive (Loss)/ Income
Balance, beginning of period at Dec. 31, 2016	$ 781,412	$ 50			$ 374,907	$ 444,320		$ (37,688)
Balance, beginning of period (in shares) at Dec. 31, 2016		51,097,687
Treasury stock, beginning of period at Dec. 31, 2016							$ (177)
Treasury stock, beginning of period (in shares) at Dec. 31, 2016							19,735
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	48,173				48,173
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures [Abstract]
Stock units vested (in shares)				140,043
Stock units withheld for employee taxes	(3,300)				(3,300)
Stock units withheld for employee taxes (in shares)				(43,479)
Proceeds from stock option exercises	54,097	$ 3			54,094
Proceeds from stock options exercises (in shares)		1,789,434
Foreign currency translation adjustments	20,065							20,065
Foreign currency translation adjustments, net of tax	20,065
Change in unrealized gains and losses on cash flow hedges, net of tax	0
Cumulative effect of the adoption of ASU | ASU 2016-09	1,740					1,740
Net income	72,760					72,760
Balance, end of period at Dec. 31, 2017	974,947	$ 53			473,874	518,820		(17,623)
Balance, end of period (in shares) at Dec. 31, 2017		52,983,685
Treasury stock, end of period at Dec. 31, 2017							$ (177)
Treasury stock, end of period (in shares) at Dec. 31, 2017							19,735
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	44,279				44,279
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures [Abstract]
Stock units vested (in shares)				222,675
Stock units withheld for employee taxes	(8,131)				(8,131)
Stock units withheld for employee taxes (in shares)				(71,334)
Proceeds from stock option exercises	34,679	$ 1			34,678
Proceeds from stock options exercises (in shares)		945,166
Foreign currency translation adjustments, net of tax	(21,338)							(21,338)
Change in unrealized gains and losses on cash flow hedges, net of tax	(2,553)							(2,553)
Cumulative effect of the adoption of ASU | ASU 2014-09	457					457
Net income	240,256					240,256
Balance, end of period at Dec. 31, 2018	$ 1,262,596	$ 54			544,700	759,533		(41,514)
Balance, end of period (in shares) at Dec. 31, 2018	54,080,192	54,080,192
Treasury stock, end of period at Dec. 31, 2018							$ (177)
Treasury stock, end of period (in shares) at Dec. 31, 2018							19,735
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 41,256				41,256
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures [Abstract]
Stock issued in connection with acquisitions (in shares)			18,787
Stock units vested (in shares)				284,922
Stock units withheld for employee taxes	(15,951)				(15,951)
Stock units withheld for employee taxes (in shares)				(95,223)
Proceeds from stock option exercises	37,047	$ 1			37,046
Proceeds from stock options exercises (in shares)		899,033
Foreign currency translation adjustments, net of tax	6,295							6,295
Change in unrealized gains and losses on cash flow hedges, net of tax	3,845							3,845
Net income	261,057					261,057
Balance, end of period at Dec. 31, 2019	$ 1,596,145	$ 55			$ 607,051	$ 1,020,590		$ (31,374)
Balance, end of period (in shares) at Dec. 31, 2019	55,187,711	55,187,711
Treasury stock, end of period at Dec. 31, 2019							$ (177)
Treasury stock, end of period (in shares) at Dec. 31, 2019							19,735