CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Common Stock [Member]	Retained Earnings [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2008	$ 194,305	$ (58)	$ 61,689	$ 132,674
Common Stock, Shares, Outstanding at Dec. 31, 2008			35,116,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	22,530			22,530
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(27)	(27)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	22,503
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	987		987
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	1,182		1,182
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			385,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	353		353
Stock Issued During Period, Shares, Other			64,000
Stock Issued During Period, Value, Other	517		517
Stock Issued During Period, Value, Stock Options Exercised	1,920		1,920
Stock Issued During Period, Shares, Employee Stock Purchase Plans			30,000
Stock Repurchased and Retired During Period, Value	(2,474)		(2,474)
Stock Repurchased and Retired During Period, Shares			(313,000)
Stock Surrendered During Period Value Payroll Tax Liabilities Stock Options Exercised	(254)		(254)
Stock Surrendered During Period Shares Payroll Tax Liabilities Stock Options Exercised			(29,000)
Stock Surrendered During Period Value Stock Options Exercised	(230)		(230)
Stock Surrendered During Period Shares Stock Options Exercised	(27,000)		(27,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2009	218,809	(85)	63,690	155,204
Common Stock, Shares, Outstanding at Dec. 31, 2009			35,226,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	12,460			12,460
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	708	708
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	237	237
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	13,405
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	399		399
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	1,294		1,294
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			239,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	378		378
Stock Issued During Period, Value, Stock Options Exercised	1,330		1,330
Stock Issued During Period, Shares, Employee Stock Purchase Plans			31,000
Stock Surrendered During Period Value Stock Options Exercised	0
Stock Surrendered During Period Shares Stock Options Exercised	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2010	235,615	860	67,091	167,664
Common Stock, Shares, Outstanding at Dec. 31, 2010			35,496,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	23,044			23,044
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(708)	(708)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	180	180
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(182)	(182)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	22,334
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	3,122		3,122
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	1,644		1,644
Stock Issued During Period, Value, New Issues	87,700		87,700
Stock Issued During Period, Shares, New Issues	5,520,000		5,520,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(1,099,000)		1,099,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	430		430
Stock Issued During Period, Value, Stock Options Exercised	8,449		8,449
Stock Issued During Period, Shares, Employee Stock Purchase Plans			31,000
Stock Surrendered During Period Value Payroll Tax Liabilities Stock Options Exercised	(953)		(953)
Stock Surrendered During Period Shares Payroll Tax Liabilities Stock Options Exercised			(60,000)
Stock Surrendered During Period Value Stock Options Exercised	(1,252)		(1,252)
Stock Surrendered During Period Shares Stock Options Exercised	(78,000)		(78,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2011	$ 357,089	$ 150	$ 166,231	$ 190,708
Common Stock, Shares, Outstanding at Dec. 31, 2011			42,008,000