LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES - Aging Analysis of Past Due Loan Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	$ 2,350,622	$ 2,313,242
Total past due and non-accrual	26,602	25,701
Total past due and still accruing	2,324,020	2,287,541
Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	88,210	109,505
Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	179,166	155,012
Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	30,247	29,662
State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	52,100	54,182
Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	288,664	301,735
Home Equity [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	52,308	49,663
Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	52,308	49,663
Commercial [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,218,514	1,121,435
Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,218,514	1,121,435
Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	347,448	327,722
Construction [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	93,965	164,326
Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	93,965	164,326
30 to 59 Days Past Due [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	6,070	8,245
Total past due and non-accrual	396	2,428
Total past due and still accruing	5,674	5,817
30 to 59 Days Past Due [Member] | Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	161	292
30 to 59 Days Past Due [Member] | Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	256	478
30 to 59 Days Past Due [Member] | Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	17	403
30 to 59 Days Past Due [Member] | State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	0
30 to 59 Days Past Due [Member] | Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	2,737	1,464
30 to 59 Days Past Due [Member] | Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	146	138
30 to 59 Days Past Due [Member] | Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,733	2,782
30 to 59 Days Past Due [Member] | Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,020	1,569
30 to 59 Days Past Due [Member] | Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	1,119
60 to 89 Days Past Due [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	4,373	2,199
Total past due and non-accrual	778	0
Total past due and still accruing	3,595	2,199
60 to 89 Days Past Due [Member] | Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	148	20
60 to 89 Days Past Due [Member] | Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	49	282
60 to 89 Days Past Due [Member] | Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	0
60 to 89 Days Past Due [Member] | State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	0
60 to 89 Days Past Due [Member] | Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,073	227
60 to 89 Days Past Due [Member] | Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	17	170
60 to 89 Days Past Due [Member] | Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	2,695	1,360
60 to 89 Days Past Due [Member] | Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	158	140
60 to 89 Days Past Due [Member] | Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	233	0
90 Days Or Greater [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	22,680	13,754
Total past due and non-accrual	22,451	13,478
Total past due and still accruing	229	276
90 Days Or Greater [Member] | Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	785	1,009
90 Days Or Greater [Member] | Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	7,500	2,336
90 Days Or Greater [Member] | Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	403	0
90 Days Or Greater [Member] | State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	0
90 Days Or Greater [Member] | Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,675	1,605
90 Days Or Greater [Member] | Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	181	148
90 Days Or Greater [Member] | Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	9,871	6,528
90 Days Or Greater [Member] | Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,982	1,845
90 Days Or Greater [Member] | Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	283	283
Total Past Due [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	33,123	24,198
Total past due and non-accrual	23,625	15,906
Total past due and still accruing	9,498	8,292
Total Past Due [Member] | Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,094	1,321
Total Past Due [Member] | Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	7,805	3,096
Total Past Due [Member] | Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	420	403
Total Past Due [Member] | State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	0	0
Total Past Due [Member] | Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	5,485	3,296
Total Past Due [Member] | Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	344	456
Total Past Due [Member] | Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	14,299	10,670
Total Past Due [Member] | Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	3,160	3,554
Total Past Due [Member] | Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	516	1,402
Current [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	2,317,499	2,289,044
Total past due and non-accrual	2,977	9,795
Total past due and still accruing	2,314,522	2,279,249
Current [Member] | Consumer [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	87,116	108,184
Current [Member] | Other Commercial Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	171,361	151,916
Current [Member] | Other Agricultural Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	29,827	29,259
Current [Member] | State and Political Subdivision Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	52,100	54,182
Current [Member] | Mortgages [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	283,179	298,439
Current [Member] | Home Equity [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	51,964	49,207
Current [Member] | Commercial [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	1,204,215	1,110,765
Current [Member] | Agricultural [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	344,288	324,168
Current [Member] | Construction [Member] | Real Estate Loans [Member]
LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES [Abstract]
Total past due	$ 93,449	$ 162,924