Loans, Credit Risk Profile Based on Rating Category and Payment Activity and on Performing and Nonperforming Status, Segregated by Class (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 2,931,385	$ 2,873,961
Consumer mortgage loans secured by real estate properties in formal foreclosure proceedings		4,200	4,400
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 1,522,668	1,498,351
Commercial [Member] | Minimum [Member]
Financing Receivable, Recorded Investment [Line Items]
Review period for loans		12 months
Commercial [Member] | Maximum [Member]
Financing Receivable, Recorded Investment [Line Items]
Review period for loans		18 months
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		$ 1,348,626	1,320,788
Commercial [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		104,082	114,431
Commercial [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		25,519	16,934
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		41,926	43,084
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		2,515	3,114
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		69,013	78,020
Commercial [Member] | Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		56,071	62,978
Commercial [Member] | Construction [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		3,979	4,931
Commercial [Member] | Construction [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		2,150	2,206
Commercial [Member] | Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		6,120	6,780
Commercial [Member] | Construction [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		693	1,125
Commercial [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,079,329	1,052,919
Commercial [Member] | Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		970,732	937,196
Commercial [Member] | Real Estate [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		66,592	71,830
Commercial [Member] | Real Estate [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		15,499	13,765
Commercial [Member] | Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		25,789	29,232
Commercial [Member] | Real Estate [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		717	896
Commercial [Member] | Equipment Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		7,353	8,514
Commercial [Member] | Equipment Lease [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		6,332	8,514
Commercial [Member] | Equipment Lease [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		0	0
Commercial [Member] | Equipment Lease [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,021	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		366,973	358,898
Commercial [Member] | Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		315,491	312,100
Commercial [Member] | Other [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		33,511	37,670
Commercial [Member] | Other [Member] | OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		6,849	963
Commercial [Member] | Other [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		10,017	7,072
Commercial [Member] | Other [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,105	1,093
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		58,973	61,750
Residential [Member] | Construction [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		58,109	61,446
Residential [Member] | Construction [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	864	304
Residential [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		708,460	707,874
Residential [Member] | Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		697,747	695,743
Residential [Member] | Real Estate [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	10,713	12,131
Residential [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		89,185	89,450
Residential [Member] | Home Equity [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		88,659	88,819
Residential [Member] | Home Equity [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	526	631
Consumer [Member] | Consumer Direct [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		129,291	126,406
Consumer [Member] | Consumer Direct [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		129,223	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		422,808	390,130
Consumer [Member] | Consumer Indirect [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		422,611	389,735
Consumer [Member] | Consumer Indirect [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile	[1]	197	395
Residential and Consumer Portfolio Segments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,408,717	1,375,610
Residential and Consumer Portfolio Segments [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan portfolio based on credit risk profile		1,396,349	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]	$ 12,368	$ 13,697

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