Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI (1) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014 Region	Mar. 31, 2013	Dec. 31, 2013
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	$ 81,153,000		$ 86,982,000
Total LHFI With No Related Allowance Recorded	22,936,000		25,643,000
Total LHFI With an Allowance Recorded	41,062,000		39,595,000
Total Carrying Amount	63,998,000		65,238,000
Related Allowance	5,541,000		5,181,000
Average Recorded Investment	64,619,000		73,800,000
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	64,000,000		65,200,000
Minimum loan amount for loan to be individually assessed for impairment	500,000
Nonaccrual financing receivable, specifically evaluated for impairment	27,600,000		31,600,000
Nonaccrual financing receivable, allowance for credit losses, specifically evaluated for impairment	1,800,000		2,200,000
Nonaccrual financing receivable, allowance for credit losses, charge-offs, specifically evaluated for impairment	46,000	986,000
Nonaccrual financing receivable specifically evaluated for impairment allowance for credit losses provisions	536,000	1,300,000
Nonaccrual financing receivable, not specifically evaluated for impairment	36,400,000		33,700,000
Nonaccrual financing receivable, allowance for credit losses, not specifically evaluated for impairment	3,700,000		3,000,000
Classified as Troubled Debt Restructuring LHFI	13,400,000		14,800,000
TDRs comprised of credits with interest only payments	9,100,000		11,100,000
Financing receivable, related allowance	1,600,000		1,600,000
Financing receivable, related charge-offs	0	60,000
Loans Secured by Real Estate [Member] | Construction Land Development And Other Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	17,722,000		24,350,000
Total LHFI With No Related Allowance Recorded	8,974,000		9,817,000
Total LHFI With an Allowance Recorded	2,285,000		3,510,000
Total Carrying Amount	11,259,000		13,327,000
Related Allowance	674,000		989,000
Average Recorded Investment	12,293,000		20,216,000
Loans Secured by Real Estate [Member] | Secured by 1-4 Family Residential Properties [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	29,417,000		26,541,000
Total LHFI With No Related Allowance Recorded	2,218,000		3,095,000
Total LHFI With an Allowance Recorded	22,367,000		18,508,000
Total Carrying Amount	24,585,000		21,603,000
Related Allowance	244,000		191,000
Average Recorded Investment	23,094,000		24,359,000
Loans Secured by Real Estate [Member] | Secured by Nonfarm, Nonresidential Properties [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	23,779,000		24,879,000
Total LHFI With No Related Allowance Recorded	9,471,000		10,225,000
Total LHFI With an Allowance Recorded	11,230,000		11,584,000
Total Carrying Amount	20,701,000		21,809,000
Related Allowance	2,123,000		2,307,000
Average Recorded Investment	21,255,000		20,049,000
Loans Secured by Real Estate [Member] | Other Loans Secured by Real Estate [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	1,363,000		1,375,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	1,307,000		1,327,000
Total Carrying Amount	1,307,000		1,327,000
Related Allowance	121,000		122,000
Average Recorded Investment	1,317,000		2,641,000
Commercial and Industrial Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	7,951,000		8,702,000
Total LHFI With No Related Allowance Recorded	2,273,000		2,506,000
Total LHFI With an Allowance Recorded	3,178,000		3,780,000
Total Carrying Amount	5,451,000		6,286,000
Related Allowance	2,111,000		1,253,000
Average Recorded Investment	5,869,000		5,513,000
Consumer Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	248,000		286,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	134,000		151,000
Total Carrying Amount	134,000		151,000
Related Allowance	1,000		2,000
Average Recorded Investment	143,000		255,000
Other Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	673,000		849,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	561,000		735,000
Total Carrying Amount	561,000		735,000
Related Allowance	267,000		317,000
Average Recorded Investment	$ 648,000		$ 767,000