Loans and Allowance for Credit Losses (Aging of Past Due Financing Receivables) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 878,597	$ 852,410
Total past due	4,538	10,143
Nonaccrual	8,729	8,972
Total loans	$ 891,864	$ 871,525
Percent of total loans, Current	98.50%	97.80%
Percent of total loans, Total past due	0.50%	1.20%
Percent of total loans, Nonaccrual	1.00%	1.00%
Percent of total loans, Total loans	100.00%	100.00%
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 2,724	$ 5,029
Percent of total loans, Total past due	0.30%	0.60%
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 1,696	$ 5,094
Percent of total loans, Total past due	0.20%	0.60%
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 118	$ 20
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	324,573	317,992
Total past due	2,348	3,873
Nonaccrual	4,270	3,903
Total loans	331,191	325,768
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,062	1,778
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,286	2,095
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	385,788	375,552
Total past due	1,947	5,977
Nonaccrual	656	1,152
Total loans	388,391	382,681
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,449	3,219
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	390	2,758
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	108
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	74,088	72,272
Total past due	101	163
Total loans	74,189	72,435
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	89	19
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	12	134
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		10
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,465	6,515
Total past due	31	25
Nonaccrual	99	99
Total loans	6,595	6,639
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	13	13
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	8	2
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	10	10
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	87,683	80,079
Total past due	111	105
Nonaccrual	3,704	3,818
Total loans	91,498	84,002
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 111
Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		$ 105