Loans - Loans Portfolio by Internal Risk Grading (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 1,295,154	$ 1,164,821	[1]
Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	230,484	208,717
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	740,303	625,218
Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	137,869	114,258
Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	602,434	510,960
Commercial real estate | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	602,434	510,960
Residential
Financing Receivable, Recorded Investment [Line Items]
Total Loans	320,127	325,855
Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	209,201	215,104
Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	110,926	110,751
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,240	5,031
Consumer | Performing
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,235	5,003
Consumer | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5	28
Pass | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	229,337	208,098
Pass | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	129,841	112,729
Pass | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	590,827	501,081
Pass | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	197,317	199,278
Pass | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	108,862	108,799
Special Mention | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	854	592
Special Mention | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,507	902
Special Mention | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,253	4,859
Special Mention | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,808	10,600
Special Mention | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,424	1,257
Substandard | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	293	27
Substandard | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,521	627
Substandard | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,354	5,020
Substandard | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,076	5,226
Substandard | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	640	695
Doubtful | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Doubtful | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Doubtful | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Doubtful | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Doubtful | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 0	$ 0

[1] Derived from audited consolidated financial statements.