CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2013	$ 543,694	$ 698	$ 542,697	$ 263,855	$ (240,241)	$ (23,315)
Net Income	67,560			67,560
Other comprehensive income (loss)	3,432					3,432
Stock-based compensation	11,045		11,045
Shares issued and forfeited, net, under stock plans including income tax benefits	30,794		(2,029)		32,823
Repurchase of common stock	(70,000)				(70,000)
Repurchase of restricted stock and performance shares for tax withholdings	(5,120)				(5,120)
Ending Balance at Dec. 31, 2014	581,405	698	551,713	331,415	(282,538)	(19,883)
Net Income	85,436			85,436
Other comprehensive income (loss)	(51,693)					(51,693)
Stock-based compensation	18,380		18,380
Shares issued and forfeited, net, under stock plans including income tax benefits	20,142		(14,089)		34,231
Issuance of 476,750 shares under stock plan portion of PAY.ON acquisition agreement		3	(3)
Issuance of 227,917 shares of common stock for acquisition of PAY.ON	5,379	1	5,378
Repurchase of restricted stock and performance shares for tax withholdings	(4,649)				(4,649)
Ending Balance at Dec. 31, 2015	654,400	702	561,379	416,851	(252,956)	(71,576)
Net Income	129,535			129,535
Other comprehensive income (loss)	(22,524)					(22,524)
Stock-based compensation	43,613		43,613
Shares issued and forfeited, net, under stock plans including income tax benefits	13,056		(5,204)		18,260
Repurchase of common stock	(60,089)				(60,089)
Repurchase of restricted stock and performance shares for tax withholdings	(2,975)				(2,975)
Cumulative effect of accounting change, ASU 2016-09 (Note 1)	(99)		556	(655)
Ending Balance at Dec. 31, 2016	$ 754,917	$ 702	$ 600,344	$ 545,731	$ (297,760)	$ (94,100)