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	$ 2,065	$ 1,794
Addition to (release of) allowance for credit losses	(160)	271
Charge-offs, net of recoveries	0	0
Total ending balance	1,905	2,065
Commercial Mortgage Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	2,026	1,728
Addition to (release of) allowance for credit losses	(146)	298
Charge-offs, net of recoveries	0	0
Total ending balance	1,880	2,026
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	39	66
Addition to (release of) allowance for credit losses	(14)	(27)
Charge-offs, net of recoveries	0	0
Total ending balance	$ 25	$ 39