Loans, Credit Risk Profile Based on Rating Category and Payment Activity and on Performing and Nonperforming Status, Segregated by Class (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	$ 1,408,793		$ 1,367,042
Residential real estate and consumer loan portfolio based on performing and nonperforming status	1,275,112		1,248,312
Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	120,248		110,779
Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	931,455		872,542
Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	10,055		8,840
Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	347,035		374,881
Real Estate Construction [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	62,105		56,075
Real Estate Mortgage [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	703,323		697,601
Home Equity [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	88,291		84,880
Consumer Direct [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	121,367		122,215
Consumer Indirect [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	300,026		287,541
Pass [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	1,225,099		1,162,559
Pass [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	100,227		85,699
Pass [Member] | Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	814,562		746,202
Pass [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	10,055		8,840
Pass [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	300,255		321,819
Watch [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	111,004		123,880
Watch [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	8,876		13,519
Watch [Member] | Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	66,827		77,561
Watch [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	0		0
Watch [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	35,301		32,800
OAEM [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	15,799		12,839
OAEM [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	1,495		0
OAEM [Member] | Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	13,436		6,639
OAEM [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	0		0
OAEM [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	868		6,200
Substandard [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	36,390		56,314
Substandard [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	5,099		7,208
Substandard [Member] | Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	23,564		37,334
Substandard [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	0		0
Substandard [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	7,727		11,772
Doubtful [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	20,501		11,450
Doubtful [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	4,551		4,353
Doubtful [Member] | Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	13,066		4,806
Doubtful [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	0		0
Doubtful [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	2,884		2,291
Performing [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	1,258,403		1,236,450
Performing [Member] | Real Estate Construction [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	61,085		55,381
Performing [Member] | Real Estate Mortgage [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	688,943		687,602
Performing [Member] | Home Equity [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	87,383		84,127
Performing [Member] | Consumer Direct [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	121,324		122,096
Performing [Member] | Consumer Indirect [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	299,668		287,244
Nonperforming [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	16,709	[1]	11,862	[1]
Nonperforming [Member] | Real Estate Construction [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	1,020	[1]	694	[1]
Nonperforming [Member] | Real Estate Mortgage [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	14,380	[1]	9,999	[1]
Nonperforming [Member] | Home Equity [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	908	[1]	753	[1]
Nonperforming [Member] | Consumer Direct [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	43	[1]	119	[1]
Nonperforming [Member] | Consumer Indirect [Member]
Credit risk profile, segregated by class [Line Items]
Residential real estate and consumer loan portfolio based on performing and nonperforming status	$ 358	[1]	$ 297	[1]

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