Loans - Aging of Recorded Investment in Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 27,372	$ 19,129
Loans Not Past Due	2,599,897	2,460,219
Total ending loans balance	2,627,269	2,479,348
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	8,394	7,608
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	8,822	4,618
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	10,156	6,903
Commercial, Industrial, and Agricultural
Financing Receivable, Past Due [Line Items]
Total Past Due	8,811	4,612
Loans Not Past Due	984,818	911,685
Total ending loans balance	993,629	916,297
Commercial, Industrial, and Agricultural | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,221	2,339
Commercial, Industrial, and Agricultural | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,607	9
Commercial, Industrial, and Agricultural | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,983	2,264
Commercial mortgages
Financing Receivable, Past Due [Line Items]
Total Past Due	10,298	4,096
Loans Not Past Due	740,036	693,680
Total ending loans balance	750,334	697,776
Commercial mortgages | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	904	758
Commercial mortgages | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5,283	3,055
Commercial mortgages | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4,111	283
Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	7,235	9,227
Loans Not Past Due	779,119	762,082
Total ending loans balance	786,354	771,309
Residential real estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,704	3,982
Residential real estate | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	774	1,257
Residential real estate | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,757	3,988
Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	897	1,115
Loans Not Past Due	88,434	84,920
Total ending loans balance	89,331	86,035
Consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	460	470
Consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	153	282
Consumer | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	284	363
Credit cards
Financing Receivable, Past Due [Line Items]
Total Past Due	131	79
Loans Not Past Due	7,153	7,544
Total ending loans balance	7,284	7,623
Credit cards | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	105	59
Credit cards | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5	15
Credit cards | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	21	5
Overdrafts
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Loans Not Past Due	337	308
Total ending loans balance	337	308
Overdrafts | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Overdrafts | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Overdrafts | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 0