Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	$ 21,915	$ 20,346	$ 19,473	$ 19,704
Charge-offs	(3,191)	(773)	(4,101)	(1,576)
Recoveries	125	76	398	215
Provision (benefit) for loan losses	5,680	1,788	8,759	3,094
Allowance for loan losses, Ending Balance	24,529	21,437	24,529	21,437
Commercial, industrial and agricultural
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	10,532	7,787	8,287	7,341
Charge-offs	(2,623)	0	(2,648)	0
Recoveries	7	4	25	8
Provision (benefit) for loan losses	1,886	317	4,138	759
Allowance for loan losses, Ending Balance	9,802	8,108	9,802	8,108
Commercial Mortgages
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	7,492	8,846	6,952	7,490
Charge-offs	0	0	0	(2)
Recoveries	2	16	174	1
Provision (benefit) for loan losses	2,134	676	2,502	2,049
Allowance for loan losses, Ending Balance	9,628	9,538	9,628	9,538
Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	1,458	1,383	1,499	2,156
Charge-offs	(19)	(146)	(162)	(244)
Recoveries	0	2	3	67
Provision (benefit) for loan losses	1,237	164	1,336	(576)
Allowance for loan losses, Ending Balance	2,676	1,403	2,676	1,403
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	2,138	2,040	2,411	2,377
Charge-offs	(413)	(513)	(1,005)	(1,062)
Recoveries	38	28	81	74
Provision (benefit) for loan losses	377	586	653	752
Allowance for loan losses, Ending Balance	2,140	2,141	2,140	2,141
Credit cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	112	105	84	103
Charge-offs	(41)	(26)	(72)	(52)
Recoveries	10	1	11	6
Provision (benefit) for loan losses	33	7	91	30
Allowance for loan losses, Ending Balance	114	87	114	87
Overdrafts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	183	185	240	237
Charge-offs	(95)	(88)	(214)	(216)
Recoveries	68	25	104	59
Provision (benefit) for loan losses	13	38	39	80
Allowance for loan losses, Ending Balance	$ 169	$ 160	$ 169	$ 160