Loans and Allowance for Loan Losses - Aging (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Aging categories of performing loans and nonaccrual loans
Current	$ 1,282,946	$ 1,095,474
Total Past Due	13,179	9,832
Total Loans	1,296,125	1,105,306	$ 1,093,800
Non-Accrual	12,846	9,699
90 Plus Days Still Accruing	0	0
Commercial
Aging categories of performing loans and nonaccrual loans
Current	919,049	777,756
Total Past Due	10,235	6,153
Total Loans	929,284	783,909	782,196
Non-Accrual	9,555	8,350
90 Plus Days Still Accruing	0	0
Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Current	426,207	377,901
Total Past Due	4,557	2,462
Total Loans	430,764	380,363
Non-Accrual	3,817	1,027
90 Plus Days Still Accruing	0	0
Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Current	365,633	300,282
Total Past Due	4,521	1,574
Total Loans	370,154	301,856
Non-Accrual	4,581	5,206
90 Plus Days Still Accruing	0	0
Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Current	127,209	99,573
Total Past Due	1,157	2,117
Total Loans	128,366	101,690
Non-Accrual	1,157	2,117
90 Plus Days Still Accruing	0	0
Residential
Aging categories of performing loans and nonaccrual loans
Current	296,324	243,177
Total Past Due	2,425	3,037
Total Loans	298,749	246,214	234,236
Non-Accrual	2,894	1,157
90 Plus Days Still Accruing	0	0
Home Equity
Aging categories of performing loans and nonaccrual loans
Current	57,450	61,907
Total Past Due	179	493
Total Loans	57,629	62,400	64,273
Non-Accrual	72	13
90 Plus Days Still Accruing	0	0
Consumer
Aging categories of performing loans and nonaccrual loans
Current	10,123	12,634
Total Past Due	340	149
Total Loans	10,463	12,783	$ 13,095
Non-Accrual	325	179
90 Plus Days Still Accruing	0	0
Financing Receivables, 30 to 59 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,217	2,687
Financing Receivables, 30 to 59 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,005	557
Financing Receivables, 30 to 59 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,005	512
Financing Receivables, 30 to 59 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	45
Financing Receivables, 30 to 59 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	24	1,879
Financing Receivables, 30 to 59 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	165	240
Financing Receivables, 30 to 59 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	23	11
Financing Receivables, 60 to 89 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	675	4,338
Financing Receivables, 60 to 89 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	218	3,391
Financing Receivables, 60 to 89 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	218	1,368
Financing Receivables, 60 to 89 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	1,149
Financing Receivables, 60 to 89 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	874
Financing Receivables, 60 to 89 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	443	707
Financing Receivables, 60 to 89 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	14	240
Financing Receivables, 60 to 89 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	11,287	2,807
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial
Aging categories of performing loans and nonaccrual loans
Total Past Due	9,012	2,205
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	3,334	582
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	4,521	380
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,157	1,243
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential
Aging categories of performing loans and nonaccrual loans
Total Past Due	1,958	451
Financing Receivables, Equal to Greater than 90 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	13
Financing Receivables, Equal to Greater than 90 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	$ 317	$ 138