Loans (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	$ 4,277,616,000	$ 3,800,203,000
Deferred loan origination costs, net	900,000	1,600,000
Residential loans held for sale	3,800,000	2,700,000
Residential Real Estate Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	651,107,000	581,511,000
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	694,799,000	611,298,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	1,072,807,000	888,879,000
Real Estate Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	123,078,000	93,977,000
Agricultural and Agricultural Real Estate Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	112,687,000	108,423,000
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	1,047,856,000	946,470,000
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	$ 575,282,000	$ 569,645,000