OFF-BALANCE-SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES - Off-Balance Sheet Arrangements, Commitments and Contingencies (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk, at fair value	$ 901,995	$ 819,605
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk, at fair value	874,557	804,715
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk, at fair value	$ 27,438	$ 14,890