CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY Statement (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity Attributable to Parent at Dec. 31, 2009	$ 242,304	$ 36	$ (65,064)	$ 324,255	$ (16,923)	$ 0
Treasury Stock, Shares at Dec. 31, 2009			(4,095,306)
Common Stock, Shares, Outstanding at Dec. 31, 2009		36,072,776
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest					4,892
Net Income (Loss) Attributable to Parent	4,892
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition				9,015
Share-based compensation expense	9,015
Stock Issued During Period, Value, Stock Options Exercised	3,638	1		3,637
Stock Issued During Period, Shares, Employee Benefit Plan		624,916
Treasury Stock, Shares, Retired			(25,817)
Stock Issued During Period, Value, Employee Stock Purchase Plan	3,364			3,364
Stock Issued During Period, Shares, Employee Stock Purchase Plans		451,014
Increase to additional paid in capital from share-based compensation	2,000			2,001
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	2,001
Stockholders' Equity Attributable to Parent at Dec. 31, 2010	265,214	37	(65,064)	342,272	(12,031)	0
Common Stock, Shares, Outstanding at Dec. 31, 2010		37,148,706
Treasury Stock, Shares at Dec. 31, 2010			(4,121,123)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest					10,389
Net Income (Loss) Attributable to Parent	10,389
Other Comprehensive Income (Loss), Net of Tax						1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1
Stock Repurchased and Retired During Period, Value	(12,573)		(12,573)
Stock Repurchased and Retired During Period, Shares			(889,511)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition				9,499
Share-based compensation expense	9,499
Stock Issued During Period, Value, Stock Options Exercised	2,737	1		2,736
Stock Issued During Period, Shares, Employee Benefit Plan		641,074
Treasury Stock, Shares, Retired			(43,174)
Stock Issued During Period, Value, Employee Stock Purchase Plan	4,050			4,050
Stock Issued During Period, Shares, Employee Stock Purchase Plans		445,965
Increase to additional paid in capital from share-based compensation	2,900			3,597
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	3,597
Stockholders' Equity Attributable to Parent at Dec. 31, 2011	282,914	38	(77,637)	362,154	(1,642)	1
Common Stock, Shares, Outstanding at Dec. 31, 2011	33,182,000	38,235,745
Treasury Stock, Shares at Dec. 31, 2011	(5,053,808)		(5,053,808)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest					16,178
Net Income (Loss) Attributable to Parent	16,178
Other Comprehensive Income (Loss), Net of Tax						130
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	130
Stock Repurchased and Retired During Period, Value	(12,363)		(12,363)
Stock Repurchased and Retired During Period, Shares			(898,168)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition				9,214
Share-based compensation expense	9,214
Stock Issued During Period, Value, Stock Options Exercised	4,548	1		4,547
Stock Issued During Period, Shares, Employee Benefit Plan		879,875
Stock Issued During Period, Value, Employee Stock Purchase Plan	4,402			4,402
Stock Issued During Period, Shares, Employee Stock Purchase Plans		377,849
Increase to additional paid in capital from share-based compensation	2,600			2,527
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	2,527
Stockholders' Equity Attributable to Parent at Dec. 31, 2012	$ 307,550	$ 39	$ (90,000)	$ 382,844	$ 14,536	$ 131
Common Stock, Shares, Outstanding at Dec. 31, 2012	33,541,000	39,493,469
Treasury Stock, Shares at Dec. 31, 2012	(5,951,976)		(5,951,976)