Investments (Accrued Investment Income) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Net Investment Income
Accrued investment income	$ 444,591	$ 333,838
Fixed maturities
Net Investment Income
Accrued investment income	388,170	272,031
Equity securities
Net Investment Income
Accrued investment income	381	220
Commercial mortgage and other loans
Net Investment Income
Accrued investment income	26,520	21,070
Policy loans
Net Investment Income
Accrued investment income	21,949	35,210
Other invested assets
Net Investment Income
Accrued investment income	0	43
Short-term investments and cash equivalents
Net Investment Income
Accrued investment income	$ 7,571	$ 5,264