Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Investment income (loss) from portfolios
Total investment income	$ 13,580	$ 8,565	$ 15,781	$ 19,471
Less: investment expenses	45	297	63	699
Net investment income	13,535	8,268	15,718	18,772
Available-for-sale securities
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	10,534	7,015	20,367	13,373
Equity securities
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	1,084	975	2,099	1,963
Limited partnerships
Investment income (loss) from portfolios
Limited partnerships	40	(290)	(10,712)	2,485
Cash equivalents and other
Investment income (loss) from portfolios
Available-for-sale, equity securities, cash equivalents, and other	$ 1,922	$ 865	$ 4,027	$ 1,650

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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