Quarterly report pursuant to Section 13 or 15(d)

Net Income Per Share (Details)

v3.5.0.2
Net Income Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Earnings Per Share, Basic, Two Class Method [Abstract]        
Net income and comprehensive income $ 11,931 $ 15,687 $ 14,964 $ 32,347
Income allocated to participating securities (93) (104) (114) (215)
Numerator for basic and diluted income per share - net income $ 11,838 $ 15,583 $ 14,850 $ 32,132
Denominator for basic income per share - weighted-average shares 30,191 30,715 30,316 30,750
Denominator for diluted income per share - adjusted weighted-average shares 30,338 30,998 30,496 31,084
Basic income per share (dollars per share) $ 0.39 $ 0.51 $ 0.49 $ 1.04
Diluted income per share (dollars per share) $ 0.39 $ 0.50 $ 0.49 $ 1.03
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     309 199
Key Employee Performance Share Based Plan [Member]        
Earnings Per Share, Basic, Two Class Method [Abstract]        
Effect of dilutive stock options and non-vested shares 30 33 29 34
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation       23
Equity Option [Member]        
Earnings Per Share, Basic, Two Class Method [Abstract]        
Effect of dilutive stock options and non-vested shares 117 250 151 300
Total number anti-dilutive options, non-vested shares, and performance shares excluded from income per diluted share computation     309 176