Loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	$ 5,406,795,000	$ 4,277,616,000
Deferred loan origination costs, net	31,800,000	25,500,000
Residential loans held for sale	100,000	3,600,000
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at January 1	2,790,000	2,537,000
New loans	569,000	750,000
Adjustment due to change in composition of related parties	376,000	(130,000)
Repayments	(363,000)	(367,000)
Balance at December 31	3,372,000	2,790,000
Residential Real Estate Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	1,041,637,000	651,107,000
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	859,026,000	694,799,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	1,328,313,000	1,072,807,000
Real Estate Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	93,247,000	123,078,000
Agricultural and Agricultural Real Estate Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	112,035,000	112,687,000
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	1,352,638,000	1,047,856,000
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loans	$ 619,899,000	$ 575,282,000