Credit Quality of Loans and Allowance for Loan Losses, Aggregate Allowance for Loan Losses and Related Party Lending (Details) (USD $)	6 Months Ended
	Jun. 30, 2014 Segment	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Number of industry segment concentration above threshold limit	1
Threshold percentage of loan portfolio (in hundredths)	10.00%
Loans exposure in oil and gas industry	$ 261,800,000
Exposure in oil and gas industry specified as percentage of total loans (in hundredths)	21.40%
Loans with exposure in commercial real estate	476,300,000
Loans on nonaccrual status	6,913,000	5,099,000
Commercial, Financial and Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans on nonaccrual status	1,779,000	1,272,000
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans with exposure in commercial real estate	379,200,000
Percentage of CRE loans secured by owner-occupied commercial properties (in hundredths)	64.00%
Loans on nonaccrual status	3,400,000
Nonaccrual status of loans specified as percentage of total CRE loans (in hundredths)	0.70%
Finance Leases Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans on nonaccrual status	0	0
Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans on nonaccrual status	$ 0	$ 0