Allowance for Probable Loan Losses (Details 3) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 61,465	$ 108,030
Commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	22,565	22,614
Commercial real estate: other construction and land development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	26,582	77,207
Commercial real estate: farmland and commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	10,086	5,486
Commercial real estate: multifamily
Loan loss allowances, financing receivable past due
Non-accrual loans, total	440	473
Residential: first lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	1,707	2,015
Residential: junior lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	57	199
Consumer
Loan loss allowances, financing receivable past due
Non-accrual loans, total	27	29
Foreign
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 1	$ 7