Investments (Allowance for Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for credit losses, beginning of year	$ 643	$ 482
Addition to (release of) allowance for losses	1,646	161
Charge Off Net Of Recoveries	0	0
Allowance for credit losses, end of year	2,289	643
Commercial mortgage and other loans
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for credit losses, beginning of year	622	455
Addition to (release of) allowance for losses	1,645	167
Charge Off Net Of Recoveries	0	0
Allowance for credit losses, end of year	2,267	622
Agricultural Property Loans
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for credit losses, beginning of year	21	27
Addition to (release of) allowance for losses	1	(6)
Charge Off Net Of Recoveries	0	0
Allowance for credit losses, end of year	22	21
Uncollateralized loans
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for credit losses, beginning of year	0	0
Addition to (release of) allowance for losses	0	0
Charge Off Net Of Recoveries	0	0
Allowance for credit losses, end of year	$ 0	$ 0