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Components of Net Realized Investment Gains (Detail) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Schedule Of Available For Sale Securities [Line Items] |  |
Total net realized investment gains | $ 136 | $ 847
Equity securities, Gross realized gains | 123 | 875
Equity securities, Gross realized losses | 0 | (3)
Equity securities, Total net realized investment gains | 123 | 872
Fixed Income Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross realized gains | 14 | 6
Gross realized losses | (1) | (31)
Total net realized investment gains | $ 13 | $ (25)

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