Loans and Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Composition of the loan portfolio
Total loans	$ 487,490	$ 419,768
Commercial
Composition of the loan portfolio
Total loans	$ 113,341	$ 96,281
Percentage of loans	23.30%	22.90%
Commercial real estate
Composition of the loan portfolio
Total loans	$ 283,135	$ 238,692
Percentage of loans	58.10%	56.90%
Residential real estate
Composition of the loan portfolio
Total loans	$ 62,071	$ 57,008
Percentage of loans	12.70%	13.60%
Consumer | Home equity
Composition of the loan portfolio
Total loans	$ 26,018	$ 25,061
Percentage of loans	5.30%	6.00%
Consumer | Other
Composition of the loan portfolio
Total loans	$ 2,925	$ 2,726
Percentage of loans	0.60%	0.60%