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Investment Funds (Schedule of Investment Funds) (Details) - USD ($) $ in Thousands			12 Months Ended
	Jul. 01, 2022	Jan. 01, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure			$ 402,000
Investment funds			1,608,548	$ 1,480,612
Income (Loss) From Investment Funds For the Year Ended			145,099	220,014	$ 54,253
Ceded to Other Companies			1,904,982	1,837,267	1,585,210
Deferred compensation trust assets			30,000	34,000
Lifson Re
Schedule of Equity Method Investments [Line Items]
Ceded to Other Companies			399,000	245,000
Percentage of reinsurance placements of share placed amounts	30.00%	22.50%
Financial services
Schedule of Equity Method Investments [Line Items]
Investment funds			465,683	431,818
Income (Loss) From Investment Funds For the Year Ended			34,030	98,893	34,763
Transportation
Schedule of Equity Method Investments [Line Items]
Investment funds			336,753	336,688
Income (Loss) From Investment Funds For the Year Ended			53,180	42,424	(616)
Real estate
Schedule of Equity Method Investments [Line Items]
Investment funds			204,644	273,690
Income (Loss) From Investment Funds For the Year Ended			48,723	29,484	7,543
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds			116,432	150,224
Income (Loss) From Investment Funds For the Year Ended			1,425	22,118	(11,039)
Infrastructure
Schedule of Equity Method Investments [Line Items]
Investment funds			115,428	12,314
Income (Loss) From Investment Funds For the Year Ended			4,603	1,372	1,672
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds			369,608	275,878
Income (Loss) From Investment Funds For the Year Ended			$ 3,138	$ 25,723	$ 21,930