Investment Information - Other investments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Schedule Of Other Investments [Line Items]
Other investments, at fair value	$ 1,578,751	$ 1,973,550
Fixed maturities
Schedule Of Other Investments [Line Items]
Other investments, at fair value	530,303	416,698
Other investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	1,005,929	1,432,553
Other investments | Lending
Schedule Of Other Investments [Line Items]
Other investments, at fair value	398,789	536,345
Other investments | Investment grade fixed income
Schedule Of Other Investments [Line Items]
Other investments, at fair value	229,262	147,810
Other investments | Term loan investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	151,649	484,950
Other investments | Private equity
Schedule Of Other Investments [Line Items]
Other investments, at fair value	117,856	91,126
Other investments | Energy
Schedule Of Other Investments [Line Items]
Other investments, at fair value	55,250	81,692
Other investments | Credit related funds
Schedule Of Other Investments [Line Items]
Other investments, at fair value	53,123	70,278
Other investments | Infrastructure
Schedule Of Other Investments [Line Items]
Other investments, at fair value	0	20,352
Short-term investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	28,614	97,806
Equity securities
Schedule Of Other Investments [Line Items]
Other investments, at fair value	$ 13,905	$ 26,493