Loans and Allowance for Loan Losses (Summary of Activity in Allowance for Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 23,011	$ 22,293	$ 20,246
Loans charged off	(4,502)	(5,025)	(5,547)
Recoveries on loans previously charged off	744	1,002	1,269
Net charge-offs	(3,758)	(4,023)	(4,278)
Provision for loan losses	3,791	4,741	6,325
Ending balance	$ 23,044	$ 23,011	$ 22,293