Summary of Calculation of Realized Gains and Losses (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Investments, Debt and Equity Securities [Abstract] | ||
| Equity securities, Total net realized investment gains | $ 123 | $ 872 |
| Less: net losses recognized during the period on equity securities sold during the period | 0 | (11) |
| Unrealized gains recognized during the reporting period on equity securities still held | $ 123 | $ 883 |