Loans and Allowance for Loan Losses (Nonaccrual Status) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest lost on nonaccrual loans	$ 600,000	$ 700,000	$ 1,700,000	$ 2,300,000
Loans on nonaccrual status	27,900,000		27,900,000		35,200,000
Loans held for investment on nonaccrual status	27,906,000		27,906,000		35,165,000
Net loans held for investment	1,296,592,000		1,296,592,000		1,185,463,000	[1]
Nonperforming [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	27,906,000		27,906,000		35,165,000
90 or more days past due and accruing	577,000		577,000		0
Net loans held for investment	28,483,000		28,483,000		35,165,000
Nonperforming [Member] | Commercial and agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	351,000		351,000		516,000
Nonperforming [Member] | Real estate - construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	2,878,000		2,878,000		4,677,000
Nonperforming [Member] | Real estate - mortgage, 1-4 family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	8,670,000		8,670,000		11,580,000
Nonperforming [Member] | Real estate - mortgage, commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	15,913,000		15,913,000		18,380,000
Nonperforming [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	$ 94,000		$ 94,000		$ 12,000

[1] Derived from audited consolidated financial statements