Loans and Allowance for Loan Losses - Summary of Recorded Investment Based on Delinquency Status (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	$ 889,931		$ 882,548		$ 862,220
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	415,753		414,005		410,781
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	75,909		68,705		73,457
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	64,486		64,983		61,012
Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	121,764		122,830		125,298
Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	199,964		199,924		178,433
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ending loans balance	12,055		12,101		13,239
Commercial Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	456,819		444,671
Total loans internally credit risk graded	499,587		490,430
Total loans not internally credit risk graded	390,344		392,118
Total ending loans balance	889,931		882,548
Commercial Credit Exposure | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	113		114
Commercial Credit Exposure | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	1,094		1,106
Commercial Credit Exposure | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	34,324		35,777
Commercial Credit Exposure | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	421,288		407,674
Commercial Credit Exposure | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	13,639		15,637
Commercial Credit Exposure | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	29,129		29,357
Commercial Credit Exposure | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		765
Commercial Credit Exposure | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	384,763		385,507
Commercial Credit Exposure | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	2,532		1,695
Commercial Credit Exposure | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	163		1,855
Commercial Credit Exposure | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	2,886		3,061
Commercial Credit Exposure | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	378,029		373,771
Total loans internally credit risk graded	415,753		414,005
Total loans not internally credit risk graded	0		0
Total ending loans balance	415,753		414,005
Commercial Credit Exposure | Commercial Real Estate | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Commercial Real Estate | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Commercial Real Estate | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	1,091		1,100
Commercial Credit Exposure | Commercial Real Estate | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	30,126		30,604
Commercial Credit Exposure | Commercial Real Estate | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	346,812		342,067
Commercial Credit Exposure | Commercial Real Estate | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	10,470		12,201
Commercial Credit Exposure | Commercial Real Estate | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	27,254		27,268
Commercial Credit Exposure | Commercial Real Estate | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		765
Commercial Credit Exposure | Commercial Real Estate | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Commercial Real Estate | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial Real Estate | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial Real Estate | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial Real Estate | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	72,259		64,690
Total loans internally credit risk graded	75,909		68,705
Total loans not internally credit risk graded	0		0
Total ending loans balance	75,909		68,705
Commercial Credit Exposure | Commercial | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	113		114
Commercial Credit Exposure | Commercial | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Commercial | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	3		6
Commercial Credit Exposure | Commercial | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	3,576		4,547
Commercial Credit Exposure | Commercial | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	68,567		60,023
Commercial Credit Exposure | Commercial | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	3,128		3,394
Commercial Credit Exposure | Commercial | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	522		621
Commercial Credit Exposure | Commercial | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Commercial | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Commercial | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Commercial | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0		0
Commercial Credit Exposure | Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	6,531	[1]	6,210	[1]
Total loans internally credit risk graded	7,925	[1]	7,720	[1]
Total loans not internally credit risk graded	56,561	[1]	57,263	[1]
Total ending loans balance	64,486	[1]	64,983	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0	[1]	0	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0	[1]	0	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0	[1]	0	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	622	[1]	626	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	5,909	[1]	5,584	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	41	[1]	42	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	1,353	[1]	1,468	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0	[1]	0	[1]
Commercial Credit Exposure | Residential Real Estate | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0	[1]	0	[1]
Commercial Credit Exposure | Residential Real Estate | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	53,834	[1]	54,416	[1]
Commercial Credit Exposure | Residential Real Estate | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	1,094	[1]	394	[1]
Commercial Credit Exposure | Residential Real Estate | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	0	[1]	1,094	[1]
Commercial Credit Exposure | Residential Real Estate | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	1,633	[1]	1,359	[1]
Commercial Credit Exposure | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Total loans internally credit risk graded	0		0
Total loans not internally credit risk graded	121,764		122,830
Total ending loans balance	121,764		122,830
Commercial Credit Exposure | Home Equity Loans | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Home Equity Loans | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Home Equity Loans | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	119,968		120,196
Commercial Credit Exposure | Home Equity Loans | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	730		630
Commercial Credit Exposure | Home Equity Loans | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	57		494
Commercial Credit Exposure | Home Equity Loans | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	1,009		1,510
Commercial Credit Exposure | Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Total loans internally credit risk graded	0		0
Total loans not internally credit risk graded	199,964		199,924
Total ending loans balance	199,964		199,924
Commercial Credit Exposure | Indirect | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Indirect | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Indirect | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Indirect | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Indirect | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Indirect | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Indirect | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Indirect | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Indirect | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Indirect | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	199,505		198,983
Commercial Credit Exposure | Indirect | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	299		645
Commercial Credit Exposure | Indirect | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	104		227
Commercial Credit Exposure | Indirect | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	56		69
Commercial Credit Exposure | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Total loans internally credit risk graded	0		0
Total loans not internally credit risk graded	12,055		12,101
Total ending loans balance	12,055		12,101
Commercial Credit Exposure | Consumer | Grade 1-Minimal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Consumer | Grade 2-Modest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Consumer | Grade 3-Better than average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Consumer | Grade 4-Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Consumer | Grade 5-Acceptable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Pass Credits	0		0
Commercial Credit Exposure | Consumer | Grade 6-Special mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Consumer | Grade 7-Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Consumer | Grade 8-Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Consumer | Grade 9-Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans internally credit risk graded	0		0
Commercial Credit Exposure | Consumer | Current loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	11,456		11,912
Commercial Credit Exposure | Consumer | 30-59 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	409		26
Commercial Credit Exposure | Consumer | 60-89 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	2		40
Commercial Credit Exposure | Consumer | 90 days past due loans not internally risk graded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans not internally credit risk graded	$ 188		$ 123

[1] Residential loans with an internal commercial credit risk grade include loans that are secured by non owner occupied 1-4 family residential properties and conventional 1-4 family residential properties.