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, 2012		52,770,392		13,363,789
Beginning balance at Dec. 31, 2012	$ 87,285	$ 1	$ 111,661	$ (67,203)	$ (57)	$ 42,883
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised and RSUs vested, net of withholdings, Shares		2,896,072
Stock options exercised and RSUs vested, net of withholdings	15,048		15,048
Stock-based compensation	4,340		4,340
Excess tax benefit from stock-based compensation	6,797		6,800
Purchase of treasury stock, Shares		(3,048,966)		3,048,966
Purchase of treasury stock	(25,000)			$ (25,000)
Shares issued related to business acquisition, Shares		107,749
Shares issued related to business acquisition	1,578		1,578
Net income	18,244					18,244
Foreign currency translation adjustments	55				55
Ending balance at Dec. 31, 2013	108,347	$ 1	139,424	$ (92,203)	(2)	61,127
Ending balance, Shares at Dec. 31, 2013		52,725,247		16,412,755
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		8,000
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 at Dec. 31, 2014	129,106	$ 1	162,641	$ (114,645)	64	81,045
Ending balance, Shares at Dec. 31, 2014		53,000,867		18,139,958
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		6,900
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 at Dec. 31, 2015	$ 157,004	$ 1	$ 178,143	$ (122,201)	$ 83	$ 100,978
Ending balance, Shares at Dec. 31, 2015		53,692,192		18,432,158