COMMITMENTS, CREDIT RISK AND CONTINGENCIES - Off-Balance Sheet Credit Risk (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Extended credit and standby letters of credit	$ 6,326,459	$ 4,424,834
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Extended credit and standby letters of credit	$ 134,951	$ 117,732