XML 108 R94.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation - Summary of the Company's Stock Option Activity (Details) - Stock Options - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Shares      
Options outstanding at the beginning of the period (in shares) 876,147 966,060  
Granted (in shares) 187,484 273,800 439,741
Exercised (in shares) (96,125) (258,699)  
Forfeited (in shares) (5,215) (80,727)  
Canceled (in shares) (5,931) (24,287)  
Options outstanding at the end of the period (in shares) 956,360 876,147 966,060
Options exercisable (in shares) 511,899    
Weighted Average Exercise Price Per Share      
Options outstanding at the beginning of the period (in dollars per share) $ 19.13 $ 17.78  
Granted (in dollars per share) 32.31 25.68  
Exercised (in dollars per share) 19.81 19.86  
Options forfeited weighted average cost (in dollars per share) 25.44 20.45  
Options canceled weighted average cost (in dollars per share) 24.36 26.98  
Options outstanding at the end of the period (in dollars per share) 21.57 $ 19.13 $ 17.78
Options exercisable (in dollars per share) $ 17.98    
Aggregate Intrinsic Value      
Options outstanding (in dollars) $ 0.6    
Options exercisable (in dollars) $ 0.6