Allowance for Probable Loan Losses (Details 3) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 43,911	$ 63,559
Commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	31,213	40,121
Commercial Real Estate: Other Construction and Land Development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	3,797	8,621
Commercial real estate: farmland and commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	7,379	11,903
Commercial real estate: multifamily
Loan loss allowances, financing receivable past due
Non-accrual loans, total	792	835
Residential: first lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	322	527
Residential: junior lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	16	1,523
Consumer
Loan loss allowances, financing receivable past due
Non-accrual loans, total	36	$ 29
Foreign
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 356