Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans, Part 7 (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Nonaccrual	$ 105,773	$ 110,458
Troubled Debt Restructurings [Member]
Financing Receivable, Modifications [Line Items]
Accruing	1,341	1,023
Nonaccrual	35,769	33,164
Total Troubled Debt Restructurings by Type	37,110	34,187
Troubled Debt Restructurings [Member] | Construction Land Development And Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Accruing	239	241
Nonaccrual	14,979	14,041
Total Troubled Debt Restructurings by Type	15,218	14,282
Troubled Debt Restructurings [Member] | Residential Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Accruing	1,102	782
Nonaccrual	4,144	3,485
Total Troubled Debt Restructurings by Type	5,246	4,267
Troubled Debt Restructurings [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	13,885	4,135
Total Troubled Debt Restructurings by Type	13,885	4,135
Troubled Debt Restructurings [Member] | Commercial And Industrial Loans [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	2,761	11,503
Total Troubled Debt Restructurings by Type	$ 2,761	$ 11,503