LOANS AND RELATED ALLOWANCE FOR LOAN LOSSES, Impaired Financing Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	$ 19,050	$ 21,220
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	13,047	14,865
Recorded Investment With Allowance	4,230	4,807
Total Recorded Investment	17,277	19,672
Related Allowance	510	735
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	18,278	21,294	$ 24,743
Interest Income Recognized	468	558	786
Interest Income Recognized Cash Basis	27	24	20
Real Estate Loans [Member] \| Mortgages [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,070	1,212
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	740	794
Recorded Investment With Allowance	123	223
Total Recorded Investment	863	1,017
Related Allowance	9	20
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	956	1,062	944
Interest Income Recognized	20	16	13
Interest Income Recognized Cash Basis	0	0	0
Real Estate Loans [Member] \| Home Equity [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	150	170
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	70	83
Recorded Investment With Allowance	57	66
Total Recorded Investment	127	149
Related Allowance	9	12
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	139	119	95
Interest Income Recognized	6	6	4
Interest Income Recognized Cash Basis	0	0	0
Real Estate Loans [Member] \| Commercial [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	9,847	12,070
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	8,323	10,723
Recorded Investment With Allowance	860	814
Total Recorded Investment	9,183	11,537
Related Allowance	95	251
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	10,354	11,756	13,907
Interest Income Recognized	358	453	506
Interest Income Recognized Cash Basis	27	24	20
Real Estate Loans [Member] \| Agricultural [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	4,811	3,900
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	2,799	1,580
Recorded Investment With Allowance	1,846	2,202
Total Recorded Investment	4,645	3,782
Related Allowance	83	151
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	3,918	4,899	4,736
Interest Income Recognized	75	78	151
Interest Income Recognized Cash Basis	0	0	0
Real Estate Loans [Member] \| Construction [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	0	0
Recorded Investment With Allowance	0	0
Total Recorded Investment	0	0
Related Allowance	0	0
Consumer [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	2	4
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	2	4
Recorded Investment With Allowance	0	0
Total Recorded Investment	2	4
Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	3	2	1
Interest Income Recognized	0	0	0
Interest Income Recognized Cash Basis	0	0	0
Other Commercial Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,908	2,517
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	1,094	1,555
Recorded Investment With Allowance	241	347
Total Recorded Investment	1,335	1,902
Related Allowance	170	147
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	1,671	2,056	3,659
Interest Income Recognized	3	1	89
Interest Income Recognized Cash Basis	0	0	0
Other Agricultural Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,262	1,347
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	19	126
Recorded Investment With Allowance	1,103	1,155
Total Recorded Investment	1,122	1,281
Related Allowance	144	154
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	1,237	1,400	1,401
Interest Income Recognized	6	4	23
Interest Income Recognized Cash Basis	$ 0	$ 0	$ 0

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524

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