Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 22,093	$ 9,924	$ 20,263	$ 5,951
Addition to (release of) allowance for expected losses	5,007	6,208	6,837	10,181
Total ending balance	27,100	16,132	27,100	16,132
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	21,133	9,704	19,665	5,847
Addition to (release of) allowance for expected losses	5,055	6,116	6,523	9,973
Total ending balance	26,188	15,820	26,188	15,820
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	960	220	598	104
Addition to (release of) allowance for expected losses	(48)	92	314	208
Total ending balance	$ 912	$ 312	$ 912	$ 312