INVESTMENT SECURITIES - Summary of Amortized Cost and Fair Value - Held-To-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortized Cost
Due in one year or less	$ 1,201
Due after one year through five years	5,395
Due after five years through ten years	41,784
Due after ten years	32,672
Amortized Cost	81,052	$ 98,211
Fair Value
Due in one year or less	1,202
Due after one year through five years	5,385
Due after five years through ten years	41,968
Due after ten years	32,365
Fair Value	$ 80,920	$ 98,261