Quarterly report pursuant to Section 13 or 15(d)

Net Income Per Share (Details)

v2.4.0.8
Net Income Per Share (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Numerator [Abstract]        
Numerator for basic and diluted income per share - net income $ 14,197 $ 12,267 $ 38,882 $ 36,707
Denominator [Abstract]        
Denominator for basic income per share - weighted-average shares 30,374 29,088 30,017 28,895
Denominator for diluted income per share - adjusted weighted-average shares 30,986 29,660 30,677 29,484
Basic income per share (dollars per share) $ 0.47 $ 0.42 $ 1.30 $ 1.27
Diluted income per share (dollars per share) $ 0.46 $ 0.41 $ 1.27 $ 1.24
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     186 234
Stock Option [Member]
        
Denominator [Abstract]        
Effect of dilutive stock options and non-vested shares 447 493 512 517
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     186 213
Key Employee Performance Share Based Plan [Member]
        
Denominator [Abstract]        
Effect of dilutive stock options and non-vested shares 13 0 9 0
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation       21
Nonvested Shares [Member]
        
Denominator [Abstract]        
Effect of dilutive stock options and non-vested shares 152 79 139 72
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation       0