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Loans (Recorded Investment by Loan Class in Current and Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 3,609,791	$ 3,557,908
Investment securities, nonaccrual	6,675	9,286
Nonaccrual with no allowance	5,597	8,616
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	16,943	6,209
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,003	1,554
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1	231
Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	17,947	7,994
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	3,585,169	3,540,628
Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	689,819	798,409
Investment securities, nonaccrual	1,046	1,975
Nonaccrual with no allowance	498	1,502
Commercial Business [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	11,489	264
Commercial Business [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		87
Commercial Business [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans
Commercial Business [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	11,489	351
Commercial Business [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	677,284	796,083
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,350,932	1,256,525
Investment securities, nonaccrual	874	2,906
Nonaccrual with no allowance	344	2,709
Commercial Mortgage [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	272	822
Commercial Mortgage [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		26
Commercial Mortgage [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans
Commercial Mortgage [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	272	848
Commercial Mortgage [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,349,786	1,252,771
Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	570,435	586,537
Investment securities, nonaccrual	2,457	2,587
Nonaccrual with no allowance	2,457	2,587
Residential Real Estate Loans [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	543	984
Residential Real Estate Loans [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	80	60
Residential Real Estate Loans [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans
Residential Real Estate Loans [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	623	1,044
Residential Real Estate Loans [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	567,355	582,906
Residential Real Estate Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	76,214	86,708
Investment securities, nonaccrual	192	323
Nonaccrual with no allowance	192	323
Residential Real Estate Lines [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	55	40
Residential Real Estate Lines [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		15
Residential Real Estate Lines [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans
Residential Real Estate Lines [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	79	55
Residential Real Estate Lines [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	75,943	86,330
Consumer Indirect [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	907,185	812,816
Investment securities, nonaccrual	2,104	1,495
Nonaccrual with no allowance	2,104	1,495
Consumer Indirect [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	4,499	3,966
Consumer Indirect [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	899	1,348
Consumer Indirect [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans
Consumer Indirect [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	5,398	5,314
Consumer Indirect [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	899,683	806,007
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	15,206	16,913
Investment securities, nonaccrual	2
Nonaccrual with no allowance	2
Other Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	85	133
Other Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	18
Other Consumer [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1	231
Other Consumer [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	86	382
Other Consumer [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 15,118	$ 16,531

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