Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Narrative) (Details)

v2.4.0.6
Stock-Based Compensation (Narrative) (Details) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Shares authorized 10,400,000    
Shares available for future grants 2,573,748    
Tax benefit for the deduction from stock-based award transactions $ 3,410,000 $ 4,702,000 $ 1,909,000
Stock-based compensation expense 7,833,000 7,870,000 6,730,000
Stock Options [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Stock-based compensation expense 3,180,000 3,550,000 3,348,000
Unrecognized costs related to share based compensation 5,407,000    
Weighted average period of recognition of unrecognized costs related to stock options, years 2 years 1 month 28 days    
Intrinsic value of stock options exercised 5,517,000 4,906,000 2,854,000
Cash received on exercises of stock options 14,600,000 10,991,000 7,333,000
Stock Options [Member] | After2000 And Before2009 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 4 years    
Expiration period, years 10    
Stock Options [Member] | During2005 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 1 year    
Expiration period, years 10    
Stock Options [Member] | After2008 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 4 years    
Expiration period, years 10    
Service Based Restricted Stock Units [Member] | After2008 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 4 years    
Service Based Restricted Stock Units [Member] | Prior To2009 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 3 years    
Performance Based Restricted Stock Units [Member] | Prior To2010 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Additional requisite service period, years 1 year    
Performance Based Restricted Stock Units [Member] | Minimum [Member] | Prior To2010 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 2 years 6 months    
Performance Based Restricted Stock Units [Member] | Minimum [Member] | After2009 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 2 years 6 months    
Performance Based Restricted Stock Units [Member] | Maximum [Member] | Prior To2010 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 3 years    
Performance Based Restricted Stock Units [Member] | Maximum [Member] | After2009 [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years 3 years    
Restricted Stock Units (RSUs) [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Stock-based compensation expense 4,653,000 4,320,000 3,382,000
Unrecognized costs related to share based compensation 9,570,000    
Weighted average period of recognition of unrecognized costs related to stock options, years 2 years 4 months 28 days    
Company withheld shares 30,299 48,059 18,721
Company withheld shares, tax obligations 1,486,000 2,974,000 853,000
Grant date fair value of vested units $ 3,874,000 $ 5,586,000 $ 2,681,000
Simplified Method [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years   5 years