Quarterly report pursuant to Section 13 or 15(d)

Net Income per Share (Details)

v3.7.0.1
Net Income per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Computation of Basic and Diluted Net Income per Share [Abstract]        
Net income $ 31,040 $ 14,291 $ 64,178 $ 27,529
Basic - weighted average common shares (in shares) 16,930 17,384 16,916 17,370
Diluted effect of common stock equivalents (in shares) 1,195 808 1,231 1,058
Diluted - weighted average common shares (in shares) 18,125 18,192 18,147 18,428
Earnings per share [Abstract]        
Basic (in dollars per share) $ 1.83 $ 0.82 $ 3.79 $ 1.58
Diluted (in dollars per share) $ 1.71 $ 0.79 $ 3.54 $ 1.49
Stock Options [Member]        
Anti-dilutive Shares Excluded from Computation of Diluted Shares [Abstract]        
Anti-dilutive stock option shares (in shares) 42 287 42 147