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, 2011
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Shares authorized 8,900,000    
Shares available for future grants 1,344,342    
Tax benefit for the deduction from stock-based award transactions $ 4,702,000 $ 1,909,000 $ 851,000
Stock-based compensation expense 7,870,000 6,730,000 6,353,000
Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Stock-based compensation expense 4,320,000 3,382,000 3,492,000
Unrecognized costs related to share based compensation 8,806,000    
Weighted average period of recognition of unrecognized costs related to stock options, years 2.34    
Company withheld shares 48,059 18,721 19,819
Company withheld shares, tax obligations 2,974,000 853,000 624,000
Grant date fair value of vested units 5,586,000 2,681,000 3,522,000
Stock Options [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Stock-based compensation expense 3,550,000 3,348,000 2,861,000
Unrecognized costs related to share based compensation 6,018,000    
Weighted average period of recognition of unrecognized costs related to stock options, years 2.33    
Intrinsic value of stock options exercised 4,906,000 2,854,000 333,000
Cash received on exercises of stock option $ 10,991,000 $ 7,333,000 $ 710,000
After 2000 And Before 2009 [Member] | Stock Options [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years four    
Expiration period, years 10    
During 2005 [Member] | Stock Options [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years one    
Expiration period, years 10    
After 2008 [Member] | Service-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years four    
After 2008 [Member] | Stock Options [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years four    
Expiration period, years 10    
Prior To 2009 [Member] | Service-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years three    
After 2009 [Member] | Maximum [Member] | Performance-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years three    
Prior To 2010 [Member] | Performance-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Additional requisite service period, years one    
Prior To 2010 [Member] | Minimum [Member] | Performance-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years two and one-half    
Prior To 2010 [Member] | Maximum [Member] | Performance-Based Restricted Stock Units [Member]
     
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Vesting period of options granted, years three