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Investment Funds (Schedule of Investment Funds) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2021	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure		$ 279,000
Investment funds		1,468,246	$ 1,621,655
(Loss) Income From Investment Funds For the Year Ended		(11,491)	16,743	$ 145,099
Ceded to Other Companies		2,238,995	2,017,539	1,904,982
Deferred compensation trust assets		38,000	36,000
Lifson Re
Schedule of Equity Method Investments [Line Items]
Ceded to Other Companies		417,000	437,000
Percentage of reinsurance placements of share placed amounts	22.50%
Financial services
Schedule of Equity Method Investments [Line Items]
Investment funds		430,163	433,407
(Loss) Income From Investment Funds For the Year Ended		(39,418)	(10,911)	34,030
Transportation
Schedule of Equity Method Investments [Line Items]
Investment funds		286,426	344,278
(Loss) Income From Investment Funds For the Year Ended		13,335	40,607	53,180
Real estate
Schedule of Equity Method Investments [Line Items]
Investment funds		178,685	201,625
(Loss) Income From Investment Funds For the Year Ended		12,195	(6,676)	48,723
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds		42,776	114,794
(Loss) Income From Investment Funds For the Year Ended		14,501	5,058	1,425
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds		378,636	396,962
(Loss) Income From Investment Funds For the Year Ended		(29,175)	(24,384)	3,138
Infrastructure
Schedule of Equity Method Investments [Line Items]
Investment funds		151,560	130,589
(Loss) Income From Investment Funds For the Year Ended		$ 17,071	$ 13,049	$ 4,603

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