Loans and Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Credit Quality Indicators
Minimum outstanding balance of loans to be reviewed on a monthly basis	$ 25
Total loans	377,922	$ 371,544
Pass
Credit Quality Indicators
Total loans	376,226	369,433
Substandard
Credit Quality Indicators
Total loans	1,696	2,111
Commercial | Commercial
Credit Quality Indicators
Total loans	64,710	61,551
Commercial | Commercial | Pass
Credit Quality Indicators
Total loans	64,459	60,961
Commercial | Commercial | Substandard
Credit Quality Indicators
Total loans	251	590
Real estate | Residential Real Estate
Credit Quality Indicators
Total loans	89,061	88,797
Real estate | Residential Real Estate | Pass
Credit Quality Indicators
Total loans	88,974	88,664
Real estate | Residential Real Estate | Substandard
Credit Quality Indicators
Total loans	87	133
Construction | Commercial Real Estate
Credit Quality Indicators
Total loans	41,186	36,829
Construction | Commercial Real Estate | Pass
Credit Quality Indicators
Total loans	41,186	36,829
Auto | Consumer
Credit Quality Indicators
Total loans	837	841
Auto | Consumer | Pass
Credit Quality Indicators
Total loans	837	841
Other | Commercial Real Estate
Credit Quality Indicators
Total loans	179,692	180,800
Other | Commercial Real Estate | Pass
Credit Quality Indicators
Total loans	178,342	179,419
Other | Commercial Real Estate | Substandard
Credit Quality Indicators
Total loans	1,350	1,381
Other | Consumer
Credit Quality Indicators
Total loans	2,436	2,726
Other | Consumer | Pass
Credit Quality Indicators
Total loans	2,428	2,719
Other | Consumer | Substandard
Credit Quality Indicators
Total loans	$ 8	$ 7