Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Detail)

v3.20.1
Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 10.3 $ 10.6
Unrecognized compensation cost on non-vested stock awards $ 83.2  
Unrecognized compensation cost on non-vested stock awards, weighted-average period of recognition 1 year 7 months 6 days  
Total vesting date fair value of stock units $ 9.6 $ 9.0
SARs [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
SARs granted 0 0
Total intrinsic value of awards exercised for SARs $ 1.6 $ 11.9