Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Detail)

v3.21.2
Share-Based Compensation - Additional Information (Detail) - USD ($)
shares in Thousands, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation expense $ 14.6 $ 12.2 $ 27.9 $ 22.5
Unrecognized compensation cost on non-vested stock awards 105.0   $ 105.0  
Unrecognized compensation cost on non-vested stock awards, weighted-average period of recognition     1 year 10 months 24 days  
Total vesting date fair value of stock units $ 1.9 $ 1.4 $ 37.4 $ 11.0
SARs [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
SARs granted 0 0 0 0
Total intrinsic value of awards exercised for SARs $ 10.3 $ 10.1 $ 24.1 $ 11.7