Loans - Aging of Recorded Investment in Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 15,364	$ 17,153
Loans Not Past Due	3,019,424	2,792,044
Total ending loans balance	3,034,788	2,809,197
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,533	5,278
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,148	2,366
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	11,683	9,509
Commercial, Industrial  and Agricultural
Financing Receivable, Past Due [Line Items]
Total Past Due	7,447	5,605
Loans Not Past Due	1,256,074	1,041,060
Total ending loans balance	1,263,521	1,046,665
Commercial, Industrial  and Agricultural | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	445	1,273
Commercial, Industrial  and Agricultural | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	451	548
Commercial, Industrial  and Agricultural | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	6,551	3,784
Commercial mortgages
Financing Receivable, Past Due [Line Items]
Total Past Due	2,754	2,939
Loans Not Past Due	862,647	811,063
Total ending loans balance	865,401	814,002
Commercial mortgages | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	162
Commercial mortgages | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0	183
Commercial mortgages | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,754	2,594
Residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	4,467	7,367
Loans Not Past Due	800,946	806,663
Total ending loans balance	805,413	814,030
Residential real estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	809	3,383
Residential real estate | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,496	1,270
Residential real estate | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,162	2,714
Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	643	1,138
Loans Not Past Due	92,766	123,647
Total ending loans balance	93,409	124,785
Consumer | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	249	412
Consumer | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	190	311
Consumer | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	204	415
Credit cards
Financing Receivable, Past Due [Line Items]
Total Past Due	53	104
Loans Not Past Due	6,707	7,465
Total ending loans balance	6,760	7,569
Credit cards | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	30	48
Credit cards | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	11	54
Credit cards | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	12	2
Overdrafts
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Loans Not Past Due	284	2,146
Total ending loans balance	284	2,146
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