Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net Investment Income [Line Items]
Gross investment income	$ 205,143	$ 181,457	$ 554,252	$ 511,789
Investment expense	(2,327)	(1,606)	(6,350)	(5,174)
Net investment income	202,816	179,851	547,902	506,615
Fixed maturity securities, including cash and cash equivalents and loans receivable
Net Investment Income [Line Items]
Gross investment income	146,051	93,031	371,724	284,704
Investment funds
Net Investment Income [Line Items]
Investment funds	36,045	69,292	121,919	169,538
Arbitrage trading account
Net Investment Income [Line Items]
Gross investment income	10,694	7,187	24,008	30,176
Equity securities
Net Investment Income [Line Items]
Gross investment income	14,650	8,462	38,303	21,854
Real estate
Net Investment Income [Line Items]
Gross investment income	$ (2,297)	$ 3,485	$ (1,702)	$ 5,517

Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

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Amount of expenses related to the generation of investment income.

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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

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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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