Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 42,682	$ 21,410	$ 37,689	$ 20,263
Addition to (release of) allowance for expected losses	(1,110)	683	3,883	1,830
Total ending balance	41,572	22,093	41,572	22,093
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	41,769	20,427	36,758	19,665
Addition to (release of) allowance for expected losses	(1,077)	706	3,934	1,468
Total ending balance	40,692	21,133	40,692	21,133
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	913	983	931	598
Addition to (release of) allowance for expected losses	(33)	(23)	(51)	362
Total ending balance	$ 880	$ 960	$ 880	$ 960