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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, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure			$ 339,000
Investment funds			1,621,655	$ 1,608,548
Income (Loss) From Investment Funds For the Year Ended			16,743	145,099	$ 220,014
Ceded to Other Companies			2,017,539	1,904,982	1,837,267
Deferred compensation trust assets			36,000	30,000
Lifson Re
Schedule of Equity Method Investments [Line Items]
Ceded to Other Companies			437,000	399,000
Percentage of reinsurance placements of share placed amounts	30.00%	22.50%
Financial services
Schedule of Equity Method Investments [Line Items]
Investment funds			433,407	465,683
Income (Loss) From Investment Funds For the Year Ended			(10,911)	34,030	98,893
Transportation
Schedule of Equity Method Investments [Line Items]
Investment funds			344,278	336,753
Income (Loss) From Investment Funds For the Year Ended			40,607	53,180	42,424
Real estate
Schedule of Equity Method Investments [Line Items]
Investment funds			201,625	204,644
Income (Loss) From Investment Funds For the Year Ended			(6,676)	48,723	29,484
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds			114,794	116,432
Income (Loss) From Investment Funds For the Year Ended			5,058	1,425	22,118
Infrastructure
Schedule of Equity Method Investments [Line Items]
Investment funds			130,589	115,428
Income (Loss) From Investment Funds For the Year Ended			13,049	4,603	1,372
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds			396,962	369,608
Income (Loss) From Investment Funds For the Year Ended			$ (24,384)	$ 3,138	$ 25,723