Investments (Schedule of Equity in (Losses) Earnings of Other Ventures, Under Equity Method) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures	$ 12,309	$ 17,194	$ 23,224
Equity method investment, dividends and distributions	33,900	30,000	36,500
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures	8,286	9,595	8,801
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures	(2,073)	3,104	10,337
Other
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures	$ 6,096	$ 4,495	$ 4,086

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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