Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance, Shares at Dec. 31, 2013		52,725,247		16,412,755
Beginning balance at Dec. 31, 2013	$ 108,347	$ 1	$ 139,424	$ (92,203)	$ (2)	$ 61,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings, Shares		2,002,823
Stock options exercised and RSUs vested, net of withholdings	9,653		9,653
Stock-based compensation	5,579		5,579
Excess tax benefit from stock-based compensation	7,985		7,985
Purchase of treasury stock, Shares		(1,727,203)		1,727,203
Purchase of treasury stock	(22,442)			$ (22,442)
Net income	19,918					19,918
Foreign currency translation adjustments	66				66
Ending balance, Shares at Dec. 31, 2014		53,000,867		18,139,958
Ending balance at Dec. 31, 2014	129,106	$ 1	162,641	$ (114,645)	64	81,045
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings, Shares		983,525
Stock options exercised and RSUs vested, net of withholdings	1,303		1,303
Stock-based compensation	7,263		7,263
Excess tax benefit from stock-based compensation	6,936		6,936
Purchase of treasury stock, Shares		(292,200)		292,200
Purchase of treasury stock	(7,556)			$ (7,556)
Net income	19,933					19,933
Foreign currency translation adjustments	19				19
Ending balance, Shares at Dec. 31, 2015		53,692,192		18,432,158
Ending balance at Dec. 31, 2015	157,004	$ 1	178,143	$ (122,201)	83	100,978
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings, Shares		421,128
Stock options exercised and RSUs vested, net of withholdings	(1,294)		(1,294)
Stock-based compensation	9,369		9,369
Excess tax benefit from stock-based compensation	1,438		1,438
Purchase of treasury stock, Shares		(1,788,069)		1,788,069
Purchase of treasury stock	(33,746)			$ (33,746)
Net income	17,297					17,297
Foreign currency translation adjustments	820				820
Ending balance, Shares at Dec. 31, 2016		52,325,251		20,220,227
Ending balance at Dec. 31, 2016	$ 150,888	$ 1	$ 187,656	$ (155,947)	$ 903	$ 118,275