Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 20,263	$ 5,951	$ 4,552
Addition to (release of) allowance for expected losses	17,426	14,312	1,399
Total ending balance	37,689	20,263	5,951
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	19,665	5,847	4,546
Addition to (release of) allowance for expected losses	17,093	13,818	1,301
Total ending balance	36,758	19,665	5,847
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	598	104	6
Addition to (release of) allowance for expected losses	333	494	98
Total ending balance	$ 931	$ 598	$ 104