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	Mar. 31, 2014		Dec. 31, 2013
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	$ 1,345,479		$ 1,367,042
Residential real estate and consumer loan portfolio based on performing and nonperforming status	1,240,029		1,248,312
Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	111,272		110,779
Commercial Secured by Real Estate [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	874,437		872,542
Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	8,122		8,840
Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	351,648		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	59,730		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	695,514		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	84,694		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	117,497		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	282,594		287,541
Pass [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	1,146,319		1,162,559
Pass [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	90,787		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	747,805		746,202
Pass [Member] | Equipment Lease [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	8,122		8,840
Pass [Member] | Commercial Other [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	299,605		321,819
Watch [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	117,102		123,880
Watch [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	9,141		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	75,684		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	32,277		32,800
OAEM [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	16,710		12,839
OAEM [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	1,094		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	9,611		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	6,005		6,200
Substandard [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	46,187		56,314
Substandard [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	5,649		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	28,986		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	11,552		11,772
Doubtful [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	19,161		11,450
Doubtful [Member] | Commercial Construction [Member]
Credit risk profile, segregated by class [Line Items]
Commercial loan portfolio based on credit risk profile	4,601		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	12,351		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	2,209		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	1,227,754		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	58,978		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	684,919		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	84,026		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	117,295		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	282,536		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	12,275	[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	752	[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	10,595	[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	668	[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	202	[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	$ 58	[1]	$ 297	[1]

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