Allowance for Credit Losses - Loan Portfolio by Impairment Methodology (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	$ 415,277	$ 428,159
Ending balance: individually evaluated for impairment	17,819	23,644
Ending balance: collectively evaluated for impairment	397,458	404,515
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	119,429	108,047
Ending balance: individually evaluated for impairment	2,423	3,857
Ending balance: collectively evaluated for impairment	117,006	104,190
Real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	242,509	259,241
Ending balance: individually evaluated for impairment	13,347	17,359
Ending balance: collectively evaluated for impairment	229,162	241,882
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	53,339	60,871
Ending balance: individually evaluated for impairment	2,049	2,428
Ending balance: collectively evaluated for impairment	$ 51,290	$ 58,443