Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 2,896	$ 2,650
Addition to (release of) allowance for credit losses	(596)	246
Charge-offs, net of recoveries	0	0
Total ending balance	2,300	2,896
Commercial Mortgage Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	2,861	2,616
Addition to (release of) allowance for credit losses	(611)	245
Charge-offs, net of recoveries	0	0
Total ending balance	2,250	2,861
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	35	34
Addition to (release of) allowance for credit losses	15	1
Charge-offs, net of recoveries	0	0
Total ending balance	$ 50	$ 35