Federal Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Composition of income tax expense (benefit)
Current	$ 1,256	$ 916	$ 451
Deferred	(129)	303	451
Federal income tax expense (benefit)	$ 1,127	$ 1,219	$ 902