v3.24.0.1
Stock-Based Compensation - Additional Information (Detail) - USD ($)
 1 Months Ended 12 Months Ended 24 Months Ended
Mar. 31, 2021
Feb. 28, 2021
Nov. 30, 2020
Jan. 31, 2023
Feb. 28, 2022
Feb. 28, 2021
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2023
Dec. 31, 2022
Jan. 01, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Total stock-based compensation expense             $ 158,200,000 $ 234,500,000 $ 386,300,000        
Intrinsic value of options             6,200,000 20,300,000 124,100,000        
Agent equity program             $ 0 41,700,000     $ 0 $ 41,700,000  
2012 Stock Incentive Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of shares available for grant (in shares)             48,600,000       48,600,000    
2012 Stock Incentive Plan | Subsequent Event                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of additional shares available for grant (in shares)                         24,200,000
2021 Equity Incentive Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of shares available for grant (in shares)   29,700,000       29,700,000              
2021 Agent Equity Program                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Total stock-based compensation expense               15,200,000 84,800,000     100,000,000  
2022 Agent Equity Program                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Total stock-based compensation expense             $ 11,600,000 41,700,000     $ 53,300,000    
Outstanding stock options                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Total stock-based compensation expense             $ 25,600,000 35,200,000 46,500,000        
Share based compensation by share based payment arrangement service based vesting period (in years)             4 years            
Unrecognized compensation cost             $ 31,400,000       31,400,000    
Unrecognized compensation costs, period of recognition (in years)             1 year 9 months 18 days            
Outstanding stock options | 2012 Stock Incentive Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Expiration period             10 years            
Restricted Stock Units                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Share based compensation by share based payment arrangement service based vesting period (in years)     4 years                    
Granted (in shares)             44,460,038            
Restricted Stock Units | Class A common stock                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Shares issued in period (in shares)             35,900,000            
Restricted Stock Units | Maximum                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Share based compensation by share based payment arrangement service based vesting period (in years)                   5 years      
Restricted Stock Units | 2012 Stock Incentive Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Expiration period             7 years            
Restricted Stock Units | 2021 Agent Equity Program                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Agent equity program                 $ 100,000,000        
Restricted Stock Units | 2021 Agent Equity Program | Class A common stock                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Granted (in shares)         13,600,000                
Restricted Stock Units | 2022 Agent Equity Program                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Granted (in shares)       14,100,000                  
Agent equity program               53,300,000       53,300,000  
Shares subject to the Employee Stock Purchase Plan | 2021 Equity Incentive Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Increase in the shares authorized for issuance as a percentage of shares outstanding (in percent)           5.00%              
Shares subject to the Employee Stock Purchase Plan | 2021 Employee Stock Purchase Plan                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Increase in the shares authorized for issuance as a percentage of shares outstanding (in percent)   1.00%                      
Number of ESPP shares authorized (in shares)   7,400,000       7,400,000              
Purchase period   6 months                      
Purchase price of common stock, percent of market price (in percent)   85.00%                      
Total stock-based compensation expense             $ 1,300,000 2,100,000          
Employee withholdings for future purchases under the ESPP             $ 1,000,000 $ 1,300,000     $ 1,000,000 $ 1,300,000  
Shares subject to the Employee Stock Purchase Plan | 2021 Employee Stock Purchase Plan | Subsequent Event                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of additional shares available for grant (in shares)                         4,700,000
Shares subject to the Employee Stock Purchase Plan | 2021 Employee Stock Purchase Plan | Class A common stock                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of shares available for grant (in shares)             14,100,000       14,100,000    
Maximum employee subscription amount   $ 12,500                      
Shares issued in period (in shares)             800,000            
Shares subject to the Employee Stock Purchase Plan | 2021 Employee Stock Purchase Plan | Maximum                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of ESPP shares authorized (in shares)   150,000,000       150,000,000              
Unvested Restricted Stock units                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Unrecognized compensation costs, period of recognition (in years)             2 years            
Amount not yet recognized             $ 147,700,000       $ 147,700,000    
IPO Based Restricted Stock Units                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Total stock-based compensation expense $ 148,500,000