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Investment Funds (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
Investment Funds (Details) - USD ($) $ in Thousands	Jul. 01, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Unfunded commitments		$ 440,000		$ 440,000
Investment funds		1,702,270		1,702,270		$ 1,480,612
Income (Loss) from Investment Funds				85,874	$ 100,246
Written premiums ceded		466,766	$ 449,055	$ 913,349	883,729
Lifson Re
Schedule of Equity Method Investments [Line Items]
Percentage of reinsurance placements of share placed amounts				22.50%
Written premiums ceded				$ 226,000	139,000
Lifson Re \| Subsequent event
Schedule of Equity Method Investments [Line Items]
Percentage of reinsurance placements of share placed amounts	30.00%
Financial services
Schedule of Equity Method Investments [Line Items]
Investment funds		275,075		275,075		273,690
Income (Loss) from Investment Funds				28,243	10,506
Transportation
Schedule of Equity Method Investments [Line Items]
Investment funds		469,474		469,474		431,818
Income (Loss) from Investment Funds				24,135	48,990
Real Estate
Schedule of Equity Method Investments [Line Items]
Investment funds		338,555		338,555		336,688
Income (Loss) from Investment Funds				25,355	17,177
Energy
Schedule of Equity Method Investments [Line Items]
Investment funds		132,728		132,728		150,224
Income (Loss) from Investment Funds				3,708	9,492
Infrastructure
Schedule of Equity Method Investments [Line Items]
Investment funds		110,491		110,491		12,314
Income (Loss) from Investment Funds				(133)	699
Other funds
Schedule of Equity Method Investments [Line Items]
Investment funds		375,947		375,947		275,878
Income (Loss) from Investment Funds				4,566	$ 13,382
Deferred compensation trust assets		$ 31,000		$ 31,000		$ 34,000