Loans (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 798,996,000	$ 788,705,000
Interest income, including accretion, on loans	13,700,000
Accretion income included in interest income	5,600,000
Loan pay offs and renewals amount included in interest income	976,000
Outstanding principal balance and the carrying amount of loan acquired [Abstract]
Outstanding principal balance	152,673,000	219,569,000
Carrying amount	141,883,000	203,981,000
Outstanding principal balance and the carrying amount of loan acquired, impaired [Abstract]
Outstanding principal balance	22,291,000	26,349,000
Carrying amount	16,953,000	20,182,000
Changes in the accretable discount on acquired loans [Abstract]
Balance, beginning of period	2,165,000
Accretion	(1,713,000)
Reclassification from nonaccretable difference	1,391,000
Balance, end of period	1,843,000
Accretion reflected	976,000
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	124,504,000	126,192,000
Commercial real estate, portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	405,354,000	404,245,000
Commercial real estate, portfolio [Member] | Construction and land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	43,386,000	48,812,000
Commercial real estate, portfolio [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	361,968,000	355,433,000
Residential real estate, portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	262,849,000	252,346,000
Residential real estate, portfolio [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	173,695,000	161,033,000
Residential real estate, portfolio [Member] | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	89,154,000	91,313,000
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 6,289,000	$ 5,922,000