Investments (Accrued Investment Income) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Net Investment Income
Accrued investment income	$ 333,838	$ 219,635
Fixed maturities
Net Investment Income
Accrued investment income	272,031	187,628
Equity securities
Net Investment Income
Accrued investment income	220	349
Commercial mortgage and other loans
Net Investment Income
Accrued investment income	21,070	13,335
Policy loans
Net Investment Income
Accrued investment income	35,210	14,525
Other invested assets
Net Investment Income
Accrued investment income	43	48
Short-term investments and cash equivalents
Net Investment Income
Accrued investment income	$ 5,264	$ 3,750