Loans and Allowance for Loan Losses (Nonaccrual Status) (Details) (USD $)	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest lost on nonaccrual loans	$ 900,000	$ 800,000
Loans on nonaccrual status	31,700,000		35,200,000
Loans held for investment on nonaccrual status	31,403,000		35,165,000
Net loans held for investment	1,245,890,000		1,185,463,000	[1]
Nonperforming [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	31,403,000		35,165,000
90 or more days past due and accruing	282,000		0
Net loans held for investment	31,685,000		35,165,000
Nonperforming [Member] | Commercial and agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	400,000		516,000
Nonperforming [Member] | Real estate - construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	2,773,000		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	9,007,000		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	19,192,000		18,380,000
Nonperforming [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment on nonaccrual status	$ 31,000		$ 12,000

[1] Derived from audited consolidated financial statements