INVESTMENT SECURITIES - Narrative (Details) $ in Millions	Jun. 30, 2018 USD ($) position security	Dec. 31, 2017 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Pledged securities, carrying value | $	$ 475.0	$ 403.3
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in security portfolio | security	586
Number of securities in unrealized loss position	388
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	316
State, county and municipal securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	61
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	11