LOANS AND ALLOWANCE FOR CREDIT LOSSES - Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Jun. 30, 2021
Recorded Investment
Total	$ 9,605
Unpaid Principal Balance
Total	10,228
Related Allowance
With an allowance recorded	1,513
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	8,067
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest Income Recognized	78
Specific reserve for loans individually evaluated, threshold		$ 150
Commercial construction
Recorded Investment
With an allowance recorded	258
Unpaid Principal Balance
With an allowance recorded	258
Related Allowance
With an allowance recorded	205
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with related allowance	203
Other commercial real estate
Recorded Investment
With no related allowance	2,001
With an allowance recorded	1,963
Unpaid Principal Balance
With no related allowance	2,047
With an allowance recorded	2,108
Related Allowance
With an allowance recorded	1,038
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with no related allowance	1,610
Average recorded investment, with related allowance	1,973
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest income recognized, with related allowance	17
Commercial
Recorded Investment
With no related allowance	1,095
With an allowance recorded	282
Unpaid Principal Balance
With no related allowance	1,254
With an allowance recorded	289
Related Allowance
With an allowance recorded	164
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with no related allowance	1,140
Average recorded investment, with related allowance	73
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest income recognized, with no related allowance	4
Agricultural
Recorded Investment
With no related allowance	361
Unpaid Principal Balance
With no related allowance	150
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with no related allowance	114
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest income recognized, with no related allowance	2
Residential mortgages
Recorded Investment
With no related allowance	2,745
With an allowance recorded	887
Unpaid Principal Balance
With no related allowance	3,165
With an allowance recorded	944
Related Allowance
With an allowance recorded	106
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with no related allowance	1,077
Average recorded investment, with related allowance	1,865
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest income recognized, with no related allowance	17
Interest income recognized, with related allowance	37
Home equity
Recorded Investment
With an allowance recorded	13
Unpaid Principal Balance
With an allowance recorded	13
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average recorded investment, with related allowance	12
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest income recognized, with related allowance	1
Total commercial real estate
Recorded Investment
Total	4,222
Unpaid Principal Balance
Total	4,413
Related Allowance
With an allowance recorded	1,243
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	3,786
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest Income Recognized	17
Total commercial and industrial
Recorded Investment
Total	1,738
Unpaid Principal Balance
Total	1,693
Related Allowance
With an allowance recorded	164
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	1,327
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest Income Recognized	6
Total residential real estate
Recorded Investment
Total	3,632
Unpaid Principal Balance
Total	4,109
Related Allowance
With an allowance recorded	106
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	2,942
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest Income Recognized	54
Total consumer
Recorded Investment
Total	13
Unpaid Principal Balance
Total	13
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	12
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Interest Income Recognized	$ 1

Allowance for Loan and Lease Loss, Minimum Aggregate Balance, Individually Evaluated for Specific Reserve.

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