COMMITMENTS AND CONTINGENCIES - Summary of the contract or notional amount of the Company's exposure to off-balance-sheet risk (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Commitments to extend credit    
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]    
Contract or notional amount $ 554,980 $ 302,591
Financial letters of credit    
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]    
Contract or notional amount 12,444 2,610
Standby letters of credit    
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]    
Contract or notional amount $ 4,898 $ 4,314