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

Fair Value Measurements - Summary of Debt Securities, Available-for-sale (Detail)

v3.21.2
Fair Value Measurements - Summary of Debt Securities, Available-for-sale (Detail) - USD ($)
$ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Adjusted basis $ 375,212 $ 368,266
Unrealized Gains 25 321
Unrealized losses (27)  
Recorded Basis 375,210 368,587
Term Deposits [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Adjusted basis 40,024  
Recorded Basis 40,024  
Asset-backed Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Adjusted basis 66,489 51,938
Unrealized Gains 6 84
Unrealized losses (18)  
Recorded Basis 66,477 52,022
Government Debt Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Adjusted basis 79,733 57,826
Unrealized Gains 5 3
Unrealized losses (3)  
Recorded Basis 79,735 57,829
Corporate Debt Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Adjusted basis 188,966 258,502
Unrealized Gains 14 234
Unrealized losses (6)  
Recorded Basis $ 188,974 $ 258,736