Investments - Summary of Amortized Cost and Estimated Fair Value of Fixed-maturity Securities (Detail) $ in Thousands |
Dec. 31, 2021
USD ($)
|
|---|---|
| Debt Securities, Available-for-Sale and Held-to-Maturity, after Allowance for Credit Loss [Abstract] | |
| Fixed-Maturity Securities, Amortized Cost, One year or less | $ 3,922 |
| Fixed-Maturity Securities, Estimated Fair Value, More than one year | 15,110 |
| Fixed-Maturity Securities, Amortized Cost, More than one year | 15,146 |
| Fixed-Maturity Securities, Amortized Cost, Total investments | 19,068 |
| Fixed-Maturity Securities, Estimated Fair Value, One year or less | 3,918 |
| Fixed-Maturity Securities, Estimated Fair Value, Total investments | $ 19,028 |