Quarterly report pursuant to Section 13 or 15(d)

Stockholders Equity and Stock Compensation - Additional Information (Detail)

v3.22.2
Stockholders Equity and Stock Compensation - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2022
Jun. 30, 2021
Jun. 30, 2022
Jun. 30, 2021
Jan. 31, 2022
Class Of Stock [Line Items]          
Stock repurchase program expiration date     Jan. 31, 2025    
Remaining to repurchase shares under Share Repurchase Program $ 450.8   $ 450.8    
Recognized stock compensation expense 15.1 $ 13.9 32.3 $ 25.5  
Unrecognized compensation cost related to nonvested common shares 114.9   $ 114.9    
Weighted average period for recognition of cost     2 years 2 months 26 days    
ESPP          
Class Of Stock [Line Items]          
Recognized stock compensation expense $ 0.7 $ 0.7 $ 1.5 $ 1.2  
Performance-Based Awards [Member]          
Class Of Stock [Line Items]          
Performance period     3 years    
Performance-Based Awards [Member] | Minimum [Member]          
Class Of Stock [Line Items]          
Payout percentage of performance awards     0.00%    
Performance-Based Awards [Member] | Maximum [Member]          
Class Of Stock [Line Items]          
Payout percentage of performance awards     200.00%    
Two Thousand Seventeen Plan | Performance-Based Awards [Member]          
Class Of Stock [Line Items]          
Number of shares that remain available for grant 2,835,299   2,835,299    
Two Thousand Seventeen Plan | Performance-Based Awards [Member] | Maximum [Member]          
Class Of Stock [Line Items]          
Number of shares that remain available for grant 2,135,299   2,135,299    
2018 ESPP [Member]          
Class Of Stock [Line Items]          
Number of shares available for sale under employee stock purchase plan 3,914,503   3,914,503    
Percentage of price of common stock purchased     85.00%    
Maximum percentage of employee's compensation to purchase common stock 15.00%   15.00%    
Class A Common Stock [Member]          
Class Of Stock [Line Items]          
Stock repurchase program authorized amount         $ 500.0
Class A Common Stock [Member] | 2018 ESPP [Member]          
Class Of Stock [Line Items]          
Number of shares available for sale under employee stock purchase plan 5,000,000   5,000,000