Federal Income Taxes (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Composition of income tax expense (benefit)
Current		$ 407	$ 1,199	$ 1,256
Deferred		1,008	(28)	(129)
Change in corporate tax rate	[1]		1,246
Federal income tax expense (benefit)		$ 1,415	$ 2,417	$ 1,127

[1] The tax act lowers the base corporate tax rate from 35% to 21% which was applied to the existing deferred tax balance.