Investments - Investment Income (Expense) Comprised Primarily of Interest and Dividends (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net Investment Income [Line Items]
Total investment income	$ 15,267	$ 11,871	$ 29,375	$ 23,138
Less: Investment expenses	(607)	(589)	(1,192)	(1,158)
Net investment income	14,660	11,282	28,183	21,980
Available-for-sale debt securities
Net Investment Income [Line Items]
Investment income	8,390	5,927	15,604	11,797
Equity securities
Net Investment Income [Line Items]
Investment income	842	868	1,736	1,921
Cash and cash equivalents
Net Investment Income [Line Items]
Investment income	5,885	4,949	11,708	9,152
Other
Net Investment Income [Line Items]
Investment income	$ 150	$ 127	$ 327	$ 268

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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Amount of expenses related to the generation of investment income.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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