SECURITIES AVAILABLE FOR SALE - Amortized cost and fair values of securities available for sale at by contractual maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost, Due in less than one year	$ 17,643
Amortized Cost, Due in one year through five years	168,090
Amortized Cost, Due after five years through ten years	80,819
Amortized Cost, Due after ten years	6,969
Amortized Cost	273,521
Securities AFS, Amortized Cost	407,871	$ 408,093
Fair Value, Due in less than one year	17,624
Fair Value, Due in one year through five years	164,969
Fair Value, Due after five years through ten years	78,904
Fair Value, Due after ten years	7,003
Fair Value	268,500
Securities available for sale (“AFS”), at fair value	400,144	405,153
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Securities AFS, Amortized Cost	134,350	157,705
Securities available for sale (“AFS”), at fair value	$ 131,644	$ 155,532