Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Net Investment Income [Line Items]
Gross investment income before expenses and fees	$ 68,016	$ 61,582	$ 133,091	$ 120,383
Investment expenses and fees	(2,132)	(1,809)	(4,170)	(3,499)
Net investment income	65,884	59,773	128,921	116,884
Fixed maturity securities available-for-sale
Net Investment Income [Line Items]
Gross investment income before expenses and fees	61,285	52,338	119,737	103,494
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Gross investment income before expenses and fees	$ 6,731	$ 9,244	$ 13,354	$ 16,889

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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