Investments - Investment Income (Expense) Comprised Primarily of Interest and Dividends (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net Investment Income [Line Items]
Total investment income	$ 13,366	$ 6,778	$ 36,504	$ 17,451
Less: Investment expenses	(611)	(704)	(1,769)	(2,114)
Net investment income	12,755	6,074	34,735	15,337
Available-for-sale debt securities
Net Investment Income [Line Items]
Investment income	6,325	4,847	18,122	13,791
Equity securities
Net Investment Income [Line Items]
Investment income	953	740	2,874	1,965
Cash and cash equivalents
Net Investment Income [Line Items]
Investment income	5,961	1,069	15,113	1,324
Other
Net Investment Income [Line Items]
Investment income	$ 127	$ 122	$ 395	$ 371

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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