Loans - Past Due (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	$ 2,623	$ 3,274
90 Days Past Due and Still Accruing	273	359
Non- Accrual Loans	1,598	2,201
Current	1,318,598	1,332,851
Total Loans	1,321,221	1,336,125	[1]
Commercial
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	282	182
90 Days Past Due and Still Accruing	0	0
Non- Accrual Loans	102	90
Current	283,975	251,484
Total Loans	284,257	251,666
Commercial real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Loans	717,195	760,848
Commercial real estate | Construction and land development
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	220	36
90 Days Past Due and Still Accruing	0	0
Non- Accrual Loans	35	36
Current	92,811	123,111
Total Loans	93,031	123,147
Commercial real estate | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	263	855
90 Days Past Due and Still Accruing	0	280
Non- Accrual Loans	233	489
Current	623,901	636,846
Total Loans	624,164	637,701
Residential
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Loans	315,280	319,183
Residential | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	1,501	1,775
90 Days Past Due and Still Accruing	255	79
Non- Accrual Loans	1,005	1,343
Current	205,755	207,551
Total Loans	207,256	209,326
Residential | Home equity
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	316	400
90 Days Past Due and Still Accruing	18	0
Non- Accrual Loans	223	243
Current	107,708	109,457
Total Loans	108,024	109,857
Consumer
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	41	26
90 Days Past Due and Still Accruing	0	0
Non- Accrual Loans	0	0
Current	4,448	4,402
Total Loans	4,489	4,428
30- 59 Days Past Due
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	741	622
30- 59 Days Past Due | Commercial
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	180	92
30- 59 Days Past Due | Commercial real estate | Construction and land development
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	185	0
30- 59 Days Past Due | Commercial real estate | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	30	86
30- 59 Days Past Due | Residential | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	230	282
30- 59 Days Past Due | Residential | Home equity
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	75	141
30- 59 Days Past Due | Consumer
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	41	21
60-89 Days Past Due
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	11	92
60-89 Days Past Due | Commercial
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	0	0
60-89 Days Past Due | Commercial real estate | Construction and land development
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	0	0
60-89 Days Past Due | Commercial real estate | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	0	0
60-89 Days Past Due | Residential | Real estate
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	11	71
60-89 Days Past Due | Residential | Home equity
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	0	16
60-89 Days Past Due | Consumer
Analysis by portfolio segment of the entity's past due loans [Abstract]
Total Past Due	$ 0	$ 5

[1] Derived from audited consolidated financial statements.