LOANS AND ALLOWANCE FOR CREDIT LOSSES Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)
Financing Receivable, Allowance for Credit Loss [Line Items]
Additional funds committed	$ 0
Business Activities Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	28,997,000
Impaired financing receivable, interest income, cash basis method	2,212,000
Business Activities Loans | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	20,179,000
Impaired financing receivable, interest income, cash basis method	693,000
Business Activities Loans | Commercial real estate | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	19,805,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	586,000
Impaired financing receivable, with related allowance, average recorded investment	374,000
Impaired financing receivable, with related allowance, interest income, cash basis method	107,000
Business Activities Loans | Commercial and industrial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	5,698,000
Impaired financing receivable, interest income, cash basis method	1,316,000
Business Activities Loans | Commercial and industrial loans | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	3,165,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	523,000
Impaired financing receivable, with related allowance, average recorded investment	2,533,000
Impaired financing receivable, with related allowance, interest income, cash basis method	793,000
Business Activities Loans | Residential mortgages
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	2,612,000
Impaired financing receivable, interest income, cash basis method	167,000
Business Activities Loans | Residential mortgages | 1 to 4 Family
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	185,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	17,000
Impaired financing receivable, with related allowance, average recorded investment	2,427,000
Impaired financing receivable, with related allowance, interest income, cash basis method	150,000
Business Activities Loans | Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	508,000
Impaired financing receivable, interest income, cash basis method	36,000
Business Activities Loans | Consumer loans | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	0
Impaired financing receivable, with no related allowance, interest income, cash basis method	0
Impaired financing receivable, with related allowance, average recorded investment	11,000
Impaired financing receivable, with related allowance, interest income, cash basis method	1,000
Business Activities Loans | Consumer loans | Home equity
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	148,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	3,000
Impaired financing receivable, with related allowance, average recorded investment	349,000
Impaired financing receivable, with related allowance, interest income, cash basis method	32,000
Acquired Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	3,991,000
Impaired financing receivable, interest income, cash basis method	278,000
Acquired Loans | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	2,608,000
Impaired financing receivable, interest income, cash basis method	176,000
Acquired Loans | Commercial real estate | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	1,603,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	117,000
Impaired financing receivable, with related allowance, average recorded investment	1,005,000
Impaired financing receivable, with related allowance, interest income, cash basis method	59,000
Acquired Loans | Commercial and industrial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	470,000
Impaired financing receivable, interest income, cash basis method	53,000
Acquired Loans | Commercial and industrial loans | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	441,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	51,000
Impaired financing receivable, with related allowance, average recorded investment	29,000
Impaired financing receivable, with related allowance, interest income, cash basis method	2,000
Acquired Loans | Residential mortgages
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	329,000
Impaired financing receivable, interest income, cash basis method	18,000
Acquired Loans | Residential mortgages | 1 to 4 Family
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	241,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	11,000
Impaired financing receivable, with related allowance, average recorded investment	88,000
Impaired financing receivable, with related allowance, interest income, cash basis method	7,000
Acquired Loans | Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, average recorded investment	584,000
Impaired financing receivable, interest income, cash basis method	31,000
Acquired Loans | Consumer loans | Other commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	0
Impaired financing receivable, with no related allowance, interest income, cash basis method	0
Impaired financing receivable, with related allowance, average recorded investment	41,000
Impaired financing receivable, with related allowance, interest income, cash basis method	2,000
Acquired Loans | Consumer loans | Home equity
Financing Receivable, Allowance for Credit Loss [Line Items]
Impaired financing receivable, with no related allowance, average recorded investment	475,000
Impaired financing receivable, with no related allowance, interest income, cash basis method	23,000
Impaired financing receivable, with related allowance, average recorded investment	68,000
Impaired financing receivable, with related allowance, interest income, cash basis method	$ 6,000