Loans and Allowance for Loan Losses - Aging (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Aging categories of performing loans and nonaccrual loans
Current	$ 1,333,697	$ 1,288,346
Total Past Due	7,224	16,236
Total Loans	1,340,921	1,304,582	$ 1,156,573
Non-Accrual	7,075	7,103
90 Plus Days Still Accruing	0	0
Commercial and Non-Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Current	957,869	928,621
Total Past Due	4,195	12,412
Total Loans	962,064	941,033	824,625
Non-Accrual	4,457	4,495
90 Plus Days Still Accruing	0	0
Commercial and Non-Residential Real Estate | Commercial Business
Aging categories of performing loans and nonaccrual loans
Current	472,847	432,097
Total Past Due	3,704	11,434
Total Loans	476,551	443,531
Non-Accrual	3,707	3,684
90 Plus Days Still Accruing	0	0
Commercial and Non-Residential Real Estate | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Current	389,336	374,880
Total Past Due	199	681
Total Loans	389,535	375,561
Non-Accrual	333	385
90 Plus Days Still Accruing	0	0
Commercial and Non-Residential Real Estate | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Current	95,686	121,644
Total Past Due	292	297
Total Loans	95,978	121,941
Non-Accrual	417	426
90 Plus Days Still Accruing	0	0
Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Current	307,936	291,665
Total Past Due	2,777	3,264
Total Loans	310,713	294,929	260,513
Non-Accrual	2,506	2,442
90 Plus Days Still Accruing	0	0
Home Equity
Aging categories of performing loans and nonaccrual loans
Current	58,457	58,575
Total Past Due	218	440
Total Loans	58,675	59,015	59,526
Non-Accrual	83	84
90 Plus Days Still Accruing	0	0
Consumer
Aging categories of performing loans and nonaccrual loans
Current	9,435	9,485
Total Past Due	34	120
Total Loans	9,469	9,605	$ 11,909
Non-Accrual	29	82
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	2,946	8,489
Financing Receivables, 30 to 59 Days Past Due | Commercial and Non-Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	364	7,061
Financing Receivables, 30 to 59 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	165	6,380
Financing Receivables, 30 to 59 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	199	681
Financing Receivables, 30 to 59 Days Past Due | Commercial and Non-Residential Real Estate | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due | Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	2,384	1,000
Financing Receivables, 30 to 59 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	193	400
Financing Receivables, 30 to 59 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	5	28
Financing Receivables, 60 to 89 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	205	2,556
Financing Receivables, 60 to 89 Days Past Due | Commercial and Non-Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	130	1,746
Financing Receivables, 60 to 89 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	130	1,746
Financing Receivables, 60 to 89 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due | Commercial and Non-Residential Real Estate | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due | Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	50	760
Financing Receivables, 60 to 89 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	25	40
Financing Receivables, 60 to 89 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	10
Financing Receivables, Equal to Greater than 90 Days Past Due
Aging categories of performing loans and nonaccrual loans
Total Past Due	4,073	5,191
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial and Non-Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	3,701	3,605
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Business
Aging categories of performing loans and nonaccrual loans
Total Past Due	3,409	3,308
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial and Non-Residential Real Estate | Commercial Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial and Non-Residential Real Estate | Acquisition & Development
Aging categories of performing loans and nonaccrual loans
Total Past Due	292	297
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential Real Estate
Aging categories of performing loans and nonaccrual loans
Total Past Due	343	1,504
Financing Receivables, Equal to Greater than 90 Days Past Due | Home Equity
Aging categories of performing loans and nonaccrual loans
Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Consumer
Aging categories of performing loans and nonaccrual loans
Total Past Due	$ 29	$ 82