Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 29, 2017	Dec. 31, 2016
Premises and Equipment
Total cost	$ 8,009		$ 7,366
Accumulated depreciation	(2,655)		(2,515)
Property, Plant and Equipment, Net, Total	5,354		4,851
Expected construction cost of new building		$ 17,900
Land
Premises and Equipment
Total cost	2,260		2,260
Buildings
Premises and Equipment
Total cost	3,547		3,140
Leasehold improvements
Premises and Equipment
Total cost	71		71
Furniture, fixtures and equipment
Premises and Equipment
Total cost	$ 2,131		$ 1,895