Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Other Invested Assets [Line Items]
Other invested assets	$ 1,207,395	$ 1,088,613
Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	1,110,254	1,040,992
Company’s investment in separate accounts
Other Invested Assets [Line Items]
Other invested assets	410	510
Derivative Instruments
Other Invested Assets [Line Items]
Other invested assets	96,731	47,111
Equity Method | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	1,043,406	971,993
Equity Method | Private equity | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	318,342	287,969
Equity Method | Hedge funds | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	633,025	576,595
Equity Method | Real estate-related | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	92,039	107,429
Fair Value | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	66,848	68,999
Fair Value | Private equity | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	57,932	59,146
Fair Value | Hedge funds | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	253	396
Fair Value | Real estate-related | Total LPs/LLCs
Other Invested Assets [Line Items]
Other invested assets	$ 8,663	$ 9,457