Allowance for Probable Loan Losses (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 63,266	$ 62,823
Commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	35,476	34,110
Commercial real estate: other construction and land development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	11,307	11,726
Commercial real estate: farmland and commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	13,344	13,775
Commercial real estate: multifamily
Loan loss allowances, financing receivable past due
Non-accrual loans, total	280	295
Residential: first lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	1,259	1,266
Residential: junior lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	1,555	1,576
Consumer
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 45	$ 75