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

Summary of Significant Accounting Policies - Summary of concentation risk by vendor (Detail)

v3.21.2
Summary of Significant Accounting Policies - Summary of concentation risk by vendor (Detail) - Cost of Goods and Service Benchmark [Member] - Supplier Concentration Risk [Member]
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Vendor A [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage 15.00% 27.00%
Vendor B [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage 11.00% 20.00%
Vendor C [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage 11.00%  
Vendor D [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage   11.00%
Vendor E [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage   10.00%