XML 106 R91.htm IDEA: XBRL DOCUMENT v3.3.1.900
Commitments and Letters of Credit - Notional Amount of Commitments and Letter of Credit Instruments (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Commitments to extend credit    
Loss Contingencies [Line Items]    
Financial instrument of credit risk $ 1,643,187 $ 1,635,948
Financial standby letters of credit    
Loss Contingencies [Line Items]    
Financial instrument of credit risk 17,843 36,075
Performance standby letters of credit    
Loss Contingencies [Line Items]    
Financial instrument of credit risk 26,497 25,915
Commercial letters of credit    
Loss Contingencies [Line Items]    
Financial instrument of credit risk $ 1,672 $ 2,611