PREMISES AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 60,773	$ 38,660
Accumulated depreciation and amortization	(13,065)	(15,241)
Premises and equipment, net	47,708	23,419
Depreciation expense	3,500	1,500	$ 1,700
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	4,849	2,474
Buildings and improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 48,952	27,448
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful live of premises and equipment	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful live of premises and equipment	39 years
Furniture and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 6,972	$ 8,738
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful live of premises and equipment	3 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful live of premises and equipment	7 years