Loans and Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Credit Quality Indicators
Minimum outstanding balance of loans to be reviewed on a monthly basis	$ 25
Total loans	362,208	$ 359,391
Pass
Credit Quality Indicators
Total loans	355,080	354,709
Special Mention
Credit Quality Indicators
Total loans	1,467	741
Substandard
Credit Quality Indicators
Total loans	5,661	3,941
Commercial | Commercial
Credit Quality Indicators
Total loans	54,851	60,388
Commercial | Commercial | Pass
Credit Quality Indicators
Total loans	53,722	59,990
Commercial | Commercial | Substandard
Credit Quality Indicators
Total loans	1,129	398
Real estate | Residential Real Estate
Credit Quality Indicators
Total loans	82,222	78,422
Real estate | Residential Real Estate | Pass
Credit Quality Indicators
Total loans	82,004	77,982
Real estate | Residential Real Estate | Special Mention
Credit Quality Indicators
Total loans	56
Real estate | Residential Real Estate | Substandard
Credit Quality Indicators
Total loans	162	440
Construction | Commercial Real Estate
Credit Quality Indicators
Total loans	52,247	38,168
Construction | Commercial Real Estate | Pass
Credit Quality Indicators
Total loans	52,247	38,168
Auto | Consumer
Credit Quality Indicators
Total loans	1,210	1,195
Auto | Consumer | Pass
Credit Quality Indicators
Total loans	1,210	1,195
Other | Commercial Real Estate
Credit Quality Indicators
Total loans	168,826	178,343
Other | Commercial Real Estate | Pass
Credit Quality Indicators
Total loans	163,055	174,507
Other | Commercial Real Estate | Special Mention
Credit Quality Indicators
Total loans	1,411	741
Other | Commercial Real Estate | Substandard
Credit Quality Indicators
Total loans	4,360	3,095
Other | Consumer
Credit Quality Indicators
Total loans	2,852	2,875
Other | Consumer | Pass
Credit Quality Indicators
Total loans	2,842	2,867
Other | Consumer | Substandard
Credit Quality Indicators
Total loans	$ 10	$ 8