Loans (Recorded Investment by Loan Class in Current and Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 4,397,864	$ 4,416,251
Investment securities, nonaccrual	26,694	26,639
Nonaccrual with no allowance	21,053	21,316
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	11,163	25,268
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,707	4,058
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	36	21
Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	12,906	29,347
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	4,358,264	4,360,265
Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	706,756	734,947
Investment securities, nonaccrual	5,956	5,664
Nonaccrual with no allowance	315	341
Commercial Business [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,950	341
Commercial Business [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Commercial Business [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Commercial Business [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,950	341
Commercial Business [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	697,850	728,942
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,048,580	2,009,269
Investment securities, nonaccrual	10,826	10,563
Nonaccrual with no allowance	10,826	10,563
Commercial Mortgage [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	5,900
Commercial Mortgage [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	36	727
Commercial Mortgage [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Commercial Mortgage [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	36	6,627
Commercial Mortgage [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,037,718	1,992,079
Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	635,849	637,173
Investment securities, nonaccrual	6,797	6,364
Nonaccrual with no allowance	6,797	6,364
Residential Real Estate Loans [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,481	2,614
Residential Real Estate Loans [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	80
Residential Real Estate Loans [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Residential Real Estate Loans [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,481	2,694
Residential Real Estate Loans [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	627,571	628,115
Residential Real Estate Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	72,307	73,972
Investment securities, nonaccrual	235	221
Nonaccrual with no allowance	235	221
Residential Real Estate Lines [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	68	163
Residential Real Estate Lines [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	119	20
Residential Real Estate Lines [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Residential Real Estate Lines [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	187	183
Residential Real Estate Lines [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	71,885	73,568
Consumer Indirect [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	889,129	915,723
Investment securities, nonaccrual	2,880	3,814
Nonaccrual with no allowance	2,880	3,814
Consumer Indirect [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	6,578	16,128
Consumer Indirect [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,546	3,204
Consumer Indirect [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Consumer Indirect [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	8,124	19,332
Consumer Indirect [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	878,125	892,577
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	45,243	45,167
Investment securities, nonaccrual	0	13
Nonaccrual with no allowance	0	13
Other Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	86	122
Other Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	6	27
Other Consumer [Member] | Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	36	21
Other Consumer [Member] | Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	128	170
Other Consumer [Member] | Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 45,115	$ 44,984