Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning of period	$ 4,657	$ 7,382
Addition to (release of) allowance for expected losses	(585)	(381)
Allowance, end of period	4,072	7,001
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning of period	4,599	7,116
Addition to (release of) allowance for expected losses	(583)	(379)
Allowance, end of period	4,016	6,737
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Allowance, beginning of period	58	266
Addition to (release of) allowance for expected losses	(2)	(2)
Allowance, end of period	$ 56	$ 264