Investments - Schedule of Analysis of Investment Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Net Investment Income [Line Items]
Investment income, gross	$ 287,091	$ 287,025
Less investment expense	(6,477)	(4,447)
Net investment income	$ 280,614	282,578
Percentage change in investment income, gross	0.00%
Percentage change in investment expense	46.00%
Percentage change in net investment income	(1.00%)
Fixed maturities available for sale
Net Investment Income [Line Items]
Investment income, gross	$ 242,210	246,098
Percentage change in investment income, gross	(2.00%)
Policy loans
Net Investment Income [Line Items]
Investment income, gross	$ 13,658	12,816
Percentage change in investment income, gross	7.00%
Mortgage loans
Net Investment Income [Line Items]
Investment income, gross	$ 6,668	6,760
Percentage change in investment income, gross	(1.00%)
Other long-term investments
Net Investment Income [Line Items]
Investment income, gross	$ 23,079	19,663
Percentage change in investment income, gross	17.00%
Short-term investments
Net Investment Income [Line Items]
Investment income, gross	$ 1,476	1,688
Percentage change in investment income, gross
Fair value option
Net Investment Income [Line Items]
Net investment income	$ 19,200	$ 18,900