Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI (1) (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014 Region	Sep. 30, 2013	Dec. 31, 2013
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	$ 105,480,000		$ 86,982,000
Total LHFI With No Related Allowance Recorded	27,585,000		25,643,000
Total LHFI With an Allowance Recorded	60,729,000		39,595,000
Total Carrying Amount	88,314,000		65,238,000
Related Allowance	10,725,000		5,181,000
Average Recorded Investment	76,777,000		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	88,300,000		65,200,000
Minimum loan amount for loan to be individually assessed for impairment	500,000
Nonaccrual financing receivable, specifically evaluated for impairment	54,100,000		31,600,000
Nonaccrual financing receivable, allowance for credit losses, specifically evaluated for impairment	9,000,000		2,200,000
Nonaccrual financing receivable, allowance for credit losses, charge-offs, specifically evaluated for impairment	55,000	2,100,000
Nonaccrual financing receivable specifically evaluated for impairment allowance for credit losses provisions	1,600,000	3,500,000
Nonaccrual financing receivable, not specifically evaluated for impairment	34,200,000		33,700,000
Nonaccrual financing receivable, allowance for credit losses, not specifically evaluated for impairment	1,700,000		3,000,000
Classified as Troubled Debt Restructuring LHFI	12,000,000	16,800,000	14,800,000
TDRs comprised of credits with interest only payments	7,900,000	12,600,000	11,100,000
Financing receivable, related allowance	1,400,000	1,700,000	1,600,000
Financing receivable, related charge-offs	62,000	703,000
Loans Secured by Real Estate [Member] | Construction Land Development and Other Land [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	27,271,000		24,350,000
Total LHFI With No Related Allowance Recorded	9,491,000		9,817,000
Total LHFI With an Allowance Recorded	10,795,000		3,510,000
Total Carrying Amount	20,286,000		13,327,000
Related Allowance	2,607,000		989,000
Average Recorded Investment	16,806,000		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	32,478,000		26,541,000
Total LHFI With No Related Allowance Recorded	1,758,000		3,095,000
Total LHFI With an Allowance Recorded	25,259,000		18,508,000
Total Carrying Amount	27,017,000		21,603,000
Related Allowance	431,000		191,000
Average Recorded Investment	24,310,000		24,359,000
Loans Secured by Real Estate [Member] | Secured by Nonfarm, Nonresidential Properties [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	26,702,000		24,879,000
Total LHFI With No Related Allowance Recorded	14,420,000		10,225,000
Total LHFI With an Allowance Recorded	9,465,000		11,584,000
Total Carrying Amount	23,885,000		21,809,000
Related Allowance	2,163,000		2,307,000
Average Recorded Investment	22,847,000		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	1,468,000		1,375,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	1,203,000		1,327,000
Total Carrying Amount	1,203,000		1,327,000
Related Allowance	57,000		122,000
Average Recorded Investment	1,265,000		2,641,000
Commercial and Industrial Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	16,624,000		8,702,000
Total LHFI With No Related Allowance Recorded	1,916,000		2,506,000
Total LHFI With an Allowance Recorded	13,262,000		3,780,000
Total Carrying Amount	15,178,000		6,286,000
Related Allowance	5,203,000		1,253,000
Average Recorded Investment	10,732,000		5,513,000
Consumer Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	239,000		286,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	160,000		151,000
Total Carrying Amount	160,000		151,000
Related Allowance	1,000		2,000
Average Recorded Investment	156,000		255,000
Other Loans [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	698,000		849,000
Total LHFI With No Related Allowance Recorded	0		0
Total LHFI With an Allowance Recorded	585,000		735,000
Total Carrying Amount	585,000		735,000
Related Allowance	263,000		317,000
Average Recorded Investment	$ 661,000		$ 767,000