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Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted ( in shares) 0 0
Estimated pretax compensation expense $ 23.0  
Expiration period in years 4 years  
Restricted Stock Units (RSUs)    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted ( in shares) 300,000 200,000
Granted, Units fair value $ 3.6 $ 3.5
Performance-based Restricted Stock Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted, Units fair value $ 4.2 $ 3.9
Granted ( in shares) 400,000 300,000
Service period in years 3 years