Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI (1) (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2013 Region	Sep. 30, 2012	Dec. 31, 2012
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	$ 96,125,000		$ 119,818,000
Total LHFI With No Related Allowance Recorded	28,637,000		23,190,000
Total LHFI With an Allowance Recorded	44,744,000		59,173,000
Total Carrying Amount	73,381,000		82,363,000
Related Allowance	9,706,000		10,504,000
Average Recorded Investment	77,871,000		96,410,000
Maximum concentration of loan as a percentage of total LHFI (in hundredths)	10.00%
Key market regions	5
Carrying amounts of nonaccrual LHFI considered for impairment analysis	73,400,000		82,400,000
Minimum loan amount for loan to be individually assessed for impairment	500,000
Nonaccrual financing receivable, specifically evaluated for impairment	32,200,000		40,600,000
Nonaccrual financing receivable, allowance for credit losses, specifically evaluated for impairment	2,000,000		5,900,000
Nonaccrual financing receivable, allowance for credit losses, charge-offs, specifically evaluated for impairment	2,100,000	11,000,000
Nonaccrual financing receivable specifically evaluated for impairment allowance for credit losses provisions	3,500,000	276,000
Nonaccrual financing receivable, not specifically evaluated for impairment	41,200,000		41,800,000
Nonaccrual financing receivable, allowance for credit losses, not specifically evaluated for impairment	7,700,000		4,600,000
Classified as Troubled Debt Restructuring LHFI	16,800,000		24,300,000
TDRs comprised of credits with interest only payments	12,600,000		21,600,000
Financing receivable, related allowance	1,700,000		4,300,000
Financing receivable, related charge-offs	703,000	5,300,000
Loans Secured by Real Estate [Member] | Construction Land Development And Other Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	26,139,000		46,558,000
Total LHFI With No Related Allowance Recorded	11,073,000		9,571,000
Total LHFI With an Allowance Recorded	3,381,000		17,534,000
Total Carrying Amount	14,454,000		27,105,000
Related Allowance	957,000		4,992,000
Average Recorded Investment	20,779,000		33,759,000
Loans Secured by Real Estate [Member] | Secured by 1-4 Family Residential Properties [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	28,078,000		35,155,000
Total LHFI With No Related Allowance Recorded	3,206,000		2,533,000
Total LHFI With an Allowance Recorded	20,509,000		24,581,000
Total Carrying Amount	23,715,000		27,114,000
Related Allowance	260,000		1,469,000
Average Recorded Investment	25,415,000		25,731,000
Loans Secured by Real Estate [Member] | Secured by Nonfarm, Nonresidential Properties [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	24,270,000		23,337,000
Total LHFI With No Related Allowance Recorded	12,391,000		8,184,000
Total LHFI With an Allowance Recorded	8,899,000		10,105,000
Total Carrying Amount	21,290,000		18,289,000
Related Allowance	2,733,000		2,296,000
Average Recorded Investment	19,790,000		21,135,000
Loans Secured by Real Estate [Member] | Other Loans Secured by Real Estate [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	543,000		6,036,000
Total LHFI With No Related Allowance Recorded	0		566,000
Total LHFI With an Allowance Recorded	503,000		3,390,000
Total Carrying Amount	503,000		3,956,000
Related Allowance	37,000		760,000
Average Recorded Investment	2,229,000		4,914,000
Commercial and Industrial Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	15,549,000		7,251,000
Total LHFI With No Related Allowance Recorded	1,918,000		2,336,000
Total LHFI With an Allowance Recorded	10,278,000		2,405,000
Total Carrying Amount	12,196,000		4,741,000
Related Allowance	5,393,000		640,000
Average Recorded Investment	8,468,000		9,444,000
Consumer Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	392,000		624,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	203,000		360,000
Total Carrying Amount	203,000		360,000
Related Allowance	2,000		5,000
Average Recorded Investment	281,000		592,000
Other Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	1,154,000		857,000
Total LHFI With No Related Allowance Recorded	49,000		0
Total LHFI With an Allowance Recorded	971,000		798,000
Total Carrying Amount	1,020,000		798,000
Related Allowance	324,000		342,000
Average Recorded Investment	$ 909,000		$ 835,000