Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	$ 24,529	$ 21,437	$ 19,473	$ 19,704
Charge-offs	(1,108)	(3,511)	(5,209)	(5,087)
Recoveries	160	163	558	378
Provision (benefit) for loan losses	3,306	2,118	12,065	5,212
Allowance for loan losses, Ending Balance	26,887	20,207	26,887	20,207
Commercial, industrial and agricultural
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	9,802	8,108	8,287	7,341
Charge-offs	(62)	(160)	(2,710)	(160)
Recoveries	15	5	40	13
Provision (benefit) for loan losses	(106)	997	4,032	1,756
Allowance for loan losses, Ending Balance	9,649	8,950	9,649	8,950
Commercial Mortgages
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	9,628	9,538	6,952	7,490
Charge-offs	(522)	(2,650)	(522)	(2,652)
Recoveries	3	65	177	66
Provision (benefit) for loan losses	2,052	30	4,554	2,079
Allowance for loan losses, Ending Balance	11,161	6,983	11,161	6,983
Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	2,676	1,403	1,499	2,156
Charge-offs	(69)	(38)	(231)	(282)
Recoveries	64	5	67	72
Provision (benefit) for loan losses	941	116	2,277	(460)
Allowance for loan losses, Ending Balance	3,612	1,486	3,612	1,486
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	2,140	2,141	2,411	2,377
Charge-offs	(305)	(547)	(1,310)	(1,609)
Recoveries	45	58	126	132
Provision (benefit) for loan losses	329	693	982	1,445
Allowance for loan losses, Ending Balance	2,209	2,345	2,209	2,345
Credit cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	114	87	84	103
Charge-offs	(48)	(3)	(120)	(55)
Recoveries	2	6	13	12
Provision (benefit) for loan losses	75	15	166	45
Allowance for loan losses, Ending Balance	143	105	143	105
Overdrafts
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Balance	169	160	240	237
Charge-offs	(102)	(113)	(316)	(329)
Recoveries	31	24	135	83
Provision (benefit) for loan losses	15	267	54	347
Allowance for loan losses, Ending Balance	$ 113	$ 338	$ 113	$ 338