XML 69 R58.htm IDEA: XBRL DOCUMENT v3.20.2
Stock-Based Compensation Plans - Additional Information (Detail) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock option compensation $ 2.8 $ 3.2
Stock Options Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number exercisable and fully vested 43,638  
Fully vested stock options with performance conditions attached 8,779  
Stock option compensation $ 2.8 3.2
Total intrinsic value exercised 4.6 2.7
Total compensation cost related to non-vested stock options not yet recognized $ 10.2  
Expected compensation cost recognized over the weighted-average period 1 year 11 months 4 days  
Stock Equivalent Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Fully vested stock options with performance conditions attached 51,164  
Total intrinsic value exercised $ 6.1 7.1
Expected compensation cost recognized over the weighted-average period 2 years 2 months 12 days  
Number of exercisable SEUs 57,696  
Compensation cost $ 3.0 $ 11.8