Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plans (Narrative) (Details)

v2.4.0.6
Stock Incentive Plans (Narrative) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2011
years
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for future awards 1,000,141    
Stock compensation expense $ 18,171 $ 13,874 $ 14,634
Income tax benefit recognized 5,804 4,713 3,945
Fair value of restricted stock and restricted stock units 22,280 13,012 17,213
Unrecognized compensation cost related to non-vested share 53,072    
Weighted-average period 1.8    
Actual tax benefit realized $ 955 $ 883 $ 395
Employee stock purchase plan issued 34,966 37,048 34,306
Length of time options exercisable, years ten    
Maximum [Member] | Stock Options [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years five    
Maximum [Member] | Restricted Stock Units Awards [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years ten    
Minimum [Member] | Stock Options [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years three    
Minimum [Member] | Restricted Stock Units Awards [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, years one