Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Stock Option Activity (Details)

v2.4.0.6
Share-Based Payments - Stock Option Activity (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 1,557 $ 1,606
Employee Stock Option [Member]
    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense 424 822
Tax benefit related to share-based expense 136 217
Unrecognized share-based compensation, net of estimated forfeitures 2,488 3,265
Employee activity - stock options [Abstract]    
Stock option grants expire (in years) 7 years  
Grants, vesting period (in years) 3 years  
Expected dividend yield (in hundredths) 1.20% 0.90%
Expected stock price volatility 43.70% 46.60%
Weighted Average Risk Free Interest Rate 0.90% 0.80%
Expected life of options (in years) 5 years 3 months 11 days 4 years 2 months 11 days
Weighted-average fair value of options (dollars per share) $ 13 $ 13
Outstanding, beginning of period (in shares) 2,874,000  
Granted (in shares) 109,000  
Exercised (in shares) (722,000)  
Forfeited (in shares) 0  
Outstanding, end of period (in shares) 2,261,000  
Exercisable, end of period (in shares) 2,050,000  
Outstanding, beginning of period (in dollars per share) $ 26  
Grants in Period (in dollars per share) $ 37  
Exercises in Period (in dollars per share) $ 25  
Forfeited in period (in dollars per share) $ 0  
Outstanding, end of period (in dollars per share) $ 27  
Exercisable, end of period (in dollars per share) $ 27  
Aggregate Intrinsic Value Outstanding, end of period 22,645  
Aggregate Intrinsic Value Exercisable, end of period $ 22,231  
Weighted-average remaining contractual term Outstanding, end of period (in years) 2 years 9 months 11 days  
Weighted-average remaining contractual term Exercisable, end of period (in years) 2 years 6 months 11 days  
Non-employee Director Stock Options [Member]
    
Employee activity - stock options [Abstract]    
Outstanding, end of period (in shares) 26,250  
Exercisable, end of period (in dollars per share) $ 23  
Weighted-average remaining contractual term Outstanding, end of period (in years) 1 year 8 months 11 days  
Non-employee Director Activity - Options [Abstract]    
Terms of options granted to non-employee directors (in years) 10