Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI (3) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Nonaccrual	$ 74,318	$ 82,363
Troubled Debt Restructurings [Member]
Financing Receivable, Modifications [Line Items]
Accruing	1,492	1,513
Nonaccrual	17,769	22,760
Total	19,261	24,273
Troubled Debt Restructurings [Member] | Construction Land Development and Other Land Loans [Member]
Financing Receivable, Modifications [Line Items]
Accruing	229	233
Nonaccrual	9,322	12,073
Total	9,551	12,306
Troubled Debt Restructurings [Member] | Secured by 1-4 Family Residential Properties [Member]
Financing Receivable, Modifications [Line Items]
Accruing	1,263	1,280
Nonaccrual	5,275	5,908
Total	6,538	7,188
Troubled Debt Restructurings [Member] | Secured by Nonfarm, Nonresidential Properties [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	2,419	4,582
Total	2,419	4,582
Troubled Debt Restructurings [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	178	197
Total	178	197
Troubled Debt Restructurings [Member] | Commercial and Industrial Loans [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0
Nonaccrual	575
Total	$ 575