FAIR VALUE MEASUREMENTS AND FAIR VALUES OF FINANCIAL INSTRUMENTS - Level 3 Valuation Techniques Nonrecurring (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	$ 7,225,000	$ 8,082,000
Related allowance	883,000	925,000
Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	6,342,000	7,157,000
Related allowance	883,000	925,000
Foreclosed assets held for sale	1,374,000	1,338,000
Residential mortgage
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	179,000	80,000
Residential mortgage \| Real estate loan
Valuation Techniques and the Unobservable Inputs
Related allowance	139,000	153,000
Commercial \| Real estate loan
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	6,480,000	6,501,000
Related allowance	672,000	691,000
Commercial \| Commercial and industrial
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	72,000	72,000
Related allowance	72,000	72,000
Impaired Loans \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	7,225,000	8,082,000
Related allowance	883,000	925,000
Fair value	6,342,000	7,157,000
Impaired Loans \| Valuation, Market Approach \| Residential mortgage \| Real estate loan \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	673,000	1,509,000
Related allowance	139,000	162,000
Fair value	$ 534,000	$ 1,347,000
Impaired Loans \| Valuation, Market Approach \| Residential mortgage \| Real estate loan \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	33.00%	31.00%
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	$ 6,480,000	$ 6,501,000
Related allowance	672,000	691,000
Fair value	$ 5,808,000	$ 5,810,000
Impaired Loans \| Valuation, Market Approach \| Commercial \| Real estate loan \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	27.00%	28.00%
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Recorded investment - with allowance	$ 72,000	$ 72,000
Related allowance	72,000	72,000
Fair value	$ 0	$ 0
Impaired Loans \| Valuation, Market Approach \| Commercial \| Commercial and industrial \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	100.00%	100.00%
Foreclosed Assets Held For Sale \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	$ 1,374,000	$ 1,338,000
Valuation allowance	0	0
Fair value	1,374,000	1,338,000
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Commercial Real Estate Receivables \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	1,195,000	1,258,000
Valuation allowance	0	0
Fair value	$ 1,195,000	$ 1,258,000
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Commercial Real Estate Receivables \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	47.00%	44.00%
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Residential mortgage \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Foreclosed assets held for sale	$ 179,000	$ 80,000
Valuation allowance	0	0
Fair value	$ 179,000	$ 80,000
Foreclosed Assets Held For Sale \| Valuation, Market Approach \| Residential mortgage \| Weighted average \| Nonrecurring fair value measurements
Valuation Techniques and the Unobservable Inputs
Discount rate	52.00%	36.00%

The fair value of foreclosed real estate.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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Amount of allowance for credit losses related to recorded investment.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

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For each period for which an income statement is required, disclosure of the changes in the allowance, including balances at end of period.

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