FAIR VALUE - Quantitative Information (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Impaired Loans: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 512	$ 1,554
Other real estate owned: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 586	$ 517
Commercial and Industrial | Other real estate owned: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	42.28%	20.80%
Commercial and Industrial | Other real estate owned: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	42.28%	20.80%
Commercial and Industrial | Other real estate owned: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	42.28%	20.80%
Commercial mortgages, other | Impaired Loans: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 512	$ 1,554
Commercial mortgages, other | Impaired Loans: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	13.30%	10.00%
Commercial mortgages, other | Impaired Loans: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	13.30%	10.00%
Commercial mortgages, other | Impaired Loans: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	13.30%	10.00%
Commercial mortgages, other | Other real estate owned: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 416	$ 111
Residential mortgages | Other real estate owned: | Non-recurring | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	20.80%
Residential mortgages | Other real estate owned: | Non-recurring | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	35.29%
Residential mortgages | Other real estate owned: | Non-recurring | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	24.09%
Residential mortgages | Other real estate owned: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 126	$ 284
Home equity lines and loans | Other real estate owned: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 44	$ 122
Home equity lines and loans | Other real estate owned: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	20.80%
Home equity lines and loans | Other real estate owned: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	20.80%
Home equity lines and loans | Other real estate owned: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	20.80%
Derivative Liabilities | Recurring | Historical trend
Information related to Level 3 non-recurring fair value measurement [Abstract]
Liabilities, fair value disclosure	$ 211	$ 365
Derivative Liabilities | Recurring | Historical trend | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	0.59%	7.30%
Derivative Liabilities | Recurring | Historical trend | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	6.59%	7.30%
Derivative Liabilities | Recurring | Historical trend | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	1.18%	7.30%