Loans, Credit Risk Profile Based on Rating Category and Payment Activity and on Performing and Nonperforming Status, Segregated by Class (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 2,938,371	$ 2,873,961
Consumer mortgage loans secured by real estate properties for which formal foreclosure proceedings are in process		3,500	4,400
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,508,097	1,498,351
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 1,335,205	1,320,788
Commercial [Member] | Pass [Member] | Minimum [Member]
Financing Receivable, Recorded Investment [Line Items]
Review period for loans		12 months
Commercial [Member] | Pass [Member] | Maximum [Member]
Financing Receivable, Recorded Investment [Line Items]
Review period for loans		18 months
Commercial [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 88,215	114,431
Commercial [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		36,389	16,934
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		47,136	43,084
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,152	3,114
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		66,998	78,020
Commercial [Member] | Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		55,315	62,978
Commercial [Member] | Construction [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		3,366	4,931
Commercial [Member] | Construction [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		2,535	2,206
Commercial [Member] | Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		5,592	6,780
Commercial [Member] | Construction [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		190	1,125
Commercial [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,085,428	1,052,919
Commercial [Member] | Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		975,383	937,196
Commercial [Member] | Real Estate [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		51,932	71,830
Commercial [Member] | Real Estate [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		25,772	13,765
Commercial [Member] | Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		31,945	29,232
Commercial [Member] | Real Estate [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		396	896
Commercial [Member] | Equipment Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		5,512	8,514
Commercial [Member] | Equipment Lease [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		5,206	8,514
Commercial [Member] | Equipment Lease [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		137	0
Commercial [Member] | Equipment Lease [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		169	0
Commercial [Member] | Equipment Lease [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		0	0
Commercial [Member] | Equipment Lease [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		0	0
Commercial [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		350,159	358,898
Commercial [Member] | Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		299,301	312,100
Commercial [Member] | Other [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		32,780	37,670
Commercial [Member] | Other [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		7,913	963
Commercial [Member] | Other [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		9,599	7,072
Commercial [Member] | Other [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		566	1,093
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		57,966	61,750
Residential [Member] | Construction [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		57,803	61,446
Residential [Member] | Construction [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	163	304
Residential [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		702,969	707,874
Residential [Member] | Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		690,414	695,743
Residential [Member] | Real Estate [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	12,555	12,131
Residential [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		91,511	89,450
Residential [Member] | Home Equity [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		90,489	88,819
Residential [Member] | Home Equity [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	1,022	631
Consumer [Member] | Consumer Direct [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		133,093	126,406
Consumer [Member] | Consumer Direct [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		133,025	126,170
Consumer [Member] | Consumer Direct [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	68	236
Consumer [Member] | Consumer Indirect [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		444,735	390,130
Consumer [Member] | Consumer Indirect [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		444,054	389,735
Consumer [Member] | Consumer Indirect [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	681	395
Residential and Consumer Portfolio Segments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,430,274	1,375,610
Residential and Consumer Portfolio Segments [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,415,785	1,361,913
Residential and Consumer Portfolio Segments [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	$ 14,489	$ 13,697

[1] A loan is considered nonperforming if it is 90 days or more past due and/or on nonaccrual.