Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Investment income (loss) from portfolios
Total investment income	$ 2,201	$ 10,906
Less: investment expenses	18	402
Net investment income	2,183	10,504
Available-for-sale securities
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	9,833	6,358
Equity securities
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	1,015	988
Limited partnerships
Investment income (loss) from portfolios
Limited partnerships	(10,752)	2,775
Cash equivalents and other
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	$ 2,105	$ 785

Interest and Dividend Income, Operating and Income (Loss) from Equity Method Investments

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Amount, after investment expense, of income earned from investments in securities and limited partnerships. Includes, but is not limited to, dividends, interest, and amount of income (loss) for proportionate share of equity method investee's income (loss).

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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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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