Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Details)

v3.20.1
Stock-Based Compensation - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended 9 Months Ended
Sep. 30, 2018
Jun. 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Mar. 18, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Granted (in dollars per share)     $ 0    
Options, outstanding, intrinsic value     $ 20.8    
Options, exercisable, intrinsic value     20.8    
Options, exercised, intrinsic value     $ 2.9    
Term for outstanding stock     5 years 1 month 6 days    
Term for exercisable stock     5 years    
Performance stock units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Target Shares Granted (in shares)     199,413    
Incentive Award Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Tax benefit from compensation expense     $ 5.2 $ 3.8  
Compensation not yet recognized, stock options     $ 15.4    
Compensation cost not yet recognized, period for recognition     1 year 10 months 24 days    
Incentive Award Plan | Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock-based compensation     $ 0.4 0.5  
Incentive Award Plan | Non-vested restricted stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Weighted average remaining contractual term   3 years      
Stock-based compensation     $ 2.3 $ 2.0  
Target Shares Granted (in shares)     385,661    
Restricted stock units, conversion of stock, conversion rights (in shares)     1    
Compensation not yet recognized, stock options     $ 7.4    
Compensation cost not yet recognized, period for recognition     2 years    
Incentive Award Plan | Performance stock units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock-based compensation $ 1.3   $ 2.6    
Minimum | Performance stock units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
PSU's that may be earned         0.00%
Maximum | Performance stock units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
PSU's that may be earned         200.00%