Quarterly report pursuant to Section 13 or 15(d)

Net Income Per Share (Details)

v3.3.0.814
Net Income Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Numerator [Abstract]        
Net income and comprehensive income $ 15,687 $ 16,744 $ 32,347 $ 44,123
Income allocated to participating securities (104)   (215)  
Numerator for basic and diluted income per share - net income $ 15,583 $ 16,744 $ 32,132 $ 44,123
Denominator [Abstract]        
Denominator for basic income per share - weighted-average shares 30,715 30,415 30,750 30,710
Denominator for diluted income per share - adjusted weighted-average shares 30,998 30,932 31,084 31,234
Basic income per share (dollars per share) $ 0.51 $ 0.55 $ 1.04 $ 1.44
Diluted income per share (dollars per share) $ 0.50 $ 0.54 $ 1.03 $ 1.41
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     199 108
Stock Option [Member]        
Denominator [Abstract]        
Effect of dilutive stock options and non-vested shares 250 480 300 483
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     176 108
Key Employee Performance Share Based Plan [Member]        
Denominator [Abstract]        
Effect of dilutive stock options and non-vested shares 33 37 34 41
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     23 0