PREMISES AND EQUIPMENT - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) renewal_option	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Property, Plant and Equipment [Abstract]
Depreciation	$ 10,014	$ 9,196	$ 9,519
Initial lease terms	10 years
Number of lease renewal options | renewal_option	2
Operating leases, rent expense	$ 7,900	$ 4,900	$ 4,500