General form of registration statement for all companies including face-amount certificate companies

Stock-based Compensation - Additional Information (Detail)

v3.21.2
Stock-based Compensation - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Mar. 31, 2021
Jan. 31, 2021
Mar. 31, 2021
Jun. 30, 2021
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Jun. 27, 2019
Stock Restriction Agreements [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Cash purchase price                 $ 19.67
CIC Restricted Stock [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Share based compensation arrangement, Number of additional shares remian available for grant under the plan 419,913   419,913 50,973          
Share based compensation arrangement, Number of equity instruments other than options, Granted           1,799,811 1,799,811    
Share based compensation arrangement, Grant date fair value based upon common stock value           $ 6.31 $ 6.31    
Stock based compensation expense             $ 0    
Unrecognized compensation expense related to nonvested shares         $ 17,484,000   11,357,000    
Average grant date fair value based on common stock value     $ 13,260 $ 29,400          
CIC Restricted stock shares forfeited         182,044        
Number of non-vested options outstanding         2,088,653        
Restricted Stock [Member] | Stock Restriction Agreements [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Stock based compensation expense         $ 4,942,000 $ 2,470,000 3,295,000 $ 1,942,000  
Unrecognized compensation expense related to nonvested shares             $ 4,942,000 $ 8,237,000  
Subsequent Event [Member] | CIC Restricted Stock [Member] | Non-Voting Common Stock [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Share based compensation arrangement, Number of equity instruments other than options, Granted 273,065 146,848              
Equity Incentive Plan [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Number of shares of common stock may be issued or issuable             2,250,000    
Equity Incentive Plan [Member] | Non-Voting Common Stock [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Number of shares of common stock may be issued or issuable           2,250,000      
Amended Equity Incentive Plan [Member] | Subsequent Event [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Number of shares of common stock may be issued or issuable 2,219,724   2,219,724 3,250,000          
Share based compensation arrangement, Number of additional shares remian available for grant under the plan       979,303          
Amended Equity Incentive Plan [Member] | Subsequent Event [Member] | Non-Voting Common Stock [Member]                  
Disclosure of Compensation Related Costs Share based Payments. [Line Items]                  
Number of shares of common stock may be issued or issuable 2,219,724   2,219,724 2,270,697 2,088,653