Investments (Allowance for Credit Losses of Available-for-Sale Fixed-Maturity Securities) - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Investments, Debt and Equity Securities [Abstract] | ||||
| Allowance for credit losses of available-for-sale debt securities | $ 0 | $ 0 | $ 0 | $ 0 |