Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 37,689	$ 20,263
Addition to (release of) allowance for expected losses	4,993	1,147
Total ending balance	42,682	21,410
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	36,758	19,665
Addition to (release of) allowance for expected losses	5,011	762
Total ending balance	41,769	20,427
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	931	598
Addition to (release of) allowance for expected losses	(18)	385
Total ending balance	$ 913	$ 983