FAIR VALUE MEASURES - Fair Value Measurements of Assets Measured at Fair Value on Non-Recurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	$ 41,608	$ 37,018
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	41,608	37,018
Impaired loans carried at fair value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	31,182	27,684
Impaired loans carried at fair value | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Impaired loans carried at fair value | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Impaired loans carried at fair value | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	31,182	27,684
Other real estate owned
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	2,734	323
Other real estate owned | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Other real estate owned | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Other real estate owned | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	2,734	323
Purchased other real estate owned
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	7,692	9,011
Purchased other real estate owned | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Purchased other real estate owned | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	0	0
Purchased other real estate owned | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets at fair value	$ 7,692	$ 9,011