ALLOWANCE FOR CREDIT LOSSES - Charge-offs and recoveries by loan type and vintage (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	$ (133)	$ (284)
Recovery	434	87
Net (charge-offs) recoveries	301	(197)
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(30)	(280)
Recovery	428	74
Net (charge-offs) recoveries	398	(206)
1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
Recovery	1	1
Net (charge-offs) recoveries	1	1
Consumer
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(103)	(4)
Recovery	4	10
Net (charge-offs) recoveries	(99)	$ 6
Other
Financing Receivable, Recorded Investment [Line Items]
Recovery	1
Net (charge-offs) recoveries	1
2020.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	3
2020. | Consumer
Financing Receivable, Recorded Investment [Line Items]
Recovery	3
Net (charge-offs) recoveries	3
2019.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	2
2019. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Recovery	2
Net (charge-offs) recoveries	2
2018.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	79
2018. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Recovery	87
Net (charge-offs) recoveries	87
2018. | Consumer
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(8)
Net (charge-offs) recoveries	(8)
2017.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	(107)
2017. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(29)
Recovery	16
Net (charge-offs) recoveries	(13)
2017. | Consumer
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(95)
Net (charge-offs) recoveries	(95)
2017. | Other
Financing Receivable, Recorded Investment [Line Items]
Recovery	1
Net (charge-offs) recoveries	1
2016.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	10
2016. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Recovery	10
Net (charge-offs) recoveries	10
Prior.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	135
Prior. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Recovery	133
Net (charge-offs) recoveries	133
Prior. | 1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
Recovery	1
Net (charge-offs) recoveries	1
Prior. | Consumer
Financing Receivable, Recorded Investment [Line Items]
Recovery	1
Net (charge-offs) recoveries	1
Revolving Loans.
Financing Receivable, Recorded Investment [Line Items]
Net (charge-offs) recoveries	179
Revolving Loans. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Charge-offs	(1)
Recovery	180
Net (charge-offs) recoveries	$ 179