LOANS AND ALLOWANCE FOR CREDIT LOSSES - Aging Analysis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	$ 1,424,988	$ 1,411,784
Nonaccrual Loans	15,663	11,204
Total Past Due Accruing and Nonaccrual Loans	18,526	22,861
Total Loans	1,424,988	1,416,135	$ 1,351,827
Financial Asset, Past Due
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	2,863	11,657
30-59 Days Past Due
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	1,608	10,816
60-89 Days Past Due
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	763	595
Greater Than 89 Days Past Due
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	492	246
Current
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	1,406,462	1,393,274
Commercial/Agricultural Real Estate
Aging analysis of the Bank's real estate and consumer loans
Total Loans		1,125,279	1,075,841
Commercial/Agricultural Real Estate | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	11,359	5,736
Total Past Due Accruing and Nonaccrual Loans	11,486	6,026
Total Loans	730,391	725,971
Commercial/Agricultural Real Estate | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	1,712	2,742
Total Past Due Accruing and Nonaccrual Loans	1,712	7,734
Total Loans	86,959	87,908
Commercial/Agricultural Real Estate | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	0	0
Total Past Due Accruing and Nonaccrual Loans	0	0
Total Loans	208,109	208,908
Commercial/Agricultural Real Estate | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	94	0
Total Past Due Accruing and Nonaccrual Loans	94	3,975
Total Loans	104,891	102,492
Commercial/Agricultural Real Estate | Financial Asset, Past Due | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	127	290
Commercial/Agricultural Real Estate | Financial Asset, Past Due | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	4,992
Commercial/Agricultural Real Estate | Financial Asset, Past Due | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Financial Asset, Past Due | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	3,975
Commercial/Agricultural Real Estate | 30-59 Days Past Due | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	127	202
Commercial/Agricultural Real Estate | 30-59 Days Past Due | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	4,992
Commercial/Agricultural Real Estate | 30-59 Days Past Due | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | 30-59 Days Past Due | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	3,975
Commercial/Agricultural Real Estate | 60-89 Days Past Due | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	88
Commercial/Agricultural Real Estate | 60-89 Days Past Due | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | 60-89 Days Past Due | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | 60-89 Days Past Due | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Greater Than 89 Days Past Due | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Greater Than 89 Days Past Due | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Greater Than 89 Days Past Due | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Greater Than 89 Days Past Due | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Commercial/Agricultural Real Estate | Current | Commercial real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	718,905	719,945
Commercial/Agricultural Real Estate | Current | Agricultural real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	85,247	80,174
Commercial/Agricultural Real Estate | Current | Multi-family real estate
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	208,109	208,908
Commercial/Agricultural Real Estate | Current | Construction and land development
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	104,797	98,517
C&I/Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total Loans		164,819	163,471
C&I/Agricultural operating | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	4	552
Total Past Due Accruing and Nonaccrual Loans	4	578
Total Loans	133,248	136,013
C&I/Agricultural operating | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	1,436	890
Total Past Due Accruing and Nonaccrual Loans	1,451	1,716
Total Loans	24,381	28,806
C&I/Agricultural operating | Financial Asset, Past Due | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	26
C&I/Agricultural operating | Financial Asset, Past Due | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	15	826
C&I/Agricultural operating | 30-59 Days Past Due | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
C&I/Agricultural operating | 30-59 Days Past Due | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	15	826
C&I/Agricultural operating | 60-89 Days Past Due | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	26
C&I/Agricultural operating | 60-89 Days Past Due | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
C&I/Agricultural operating | Greater Than 89 Days Past Due | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
C&I/Agricultural operating | Greater Than 89 Days Past Due | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
C&I/Agricultural operating | Current | Commercial and industrial
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	133,244	135,435
C&I/Agricultural operating | Current | Agricultural operating
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	22,930	27,090
Residential Mortgage
Aging analysis of the Bank's real estate and consumer loans
Total Loans		108,651	91,994
Residential Mortgage | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	1,029	1,253
Total Past Due Accruing and Nonaccrual Loans	3,251	2,735
Total Loans	119,118	105,389
Residential Mortgage | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	0	0
Total Past Due Accruing and Nonaccrual Loans	456	0
Total Loans	3,216	3,262
Residential Mortgage | Financial Asset, Past Due | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	2,222	1,482
Residential Mortgage | Financial Asset, Past Due | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	456	0
Residential Mortgage | 30-59 Days Past Due | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	973	767
Residential Mortgage | 30-59 Days Past Due | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	456	0
Residential Mortgage | 60-89 Days Past Due | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	757	479
Residential Mortgage | 60-89 Days Past Due | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Residential Mortgage | Greater Than 89 Days Past Due | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	492	236
Residential Mortgage | Greater Than 89 Days Past Due | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Residential Mortgage | Current | Residential mortgage
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	115,867	102,654
Residential Mortgage | Current | Purchased HELOC loans
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	2,760	3,262
Consumer Installment
Aging analysis of the Bank's real estate and consumer loans
Total Loans		17,386	$ 20,521
Consumer Installment | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	27	27
Total Past Due Accruing and Nonaccrual Loans	44	42
Total Loans	8,189	10,236
Consumer Installment | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Nonaccrual Loans	2	4
Total Past Due Accruing and Nonaccrual Loans	28	55
Total Loans	6,486	7,150
Consumer Installment | Financial Asset, Past Due | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	17	15
Consumer Installment | Financial Asset, Past Due | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	26	51
Consumer Installment | 30-59 Days Past Due | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	17	15
Consumer Installment | 30-59 Days Past Due | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	20	39
Consumer Installment | 60-89 Days Past Due | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Consumer Installment | 60-89 Days Past Due | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	6	2
Consumer Installment | Greater Than 89 Days Past Due | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	0
Consumer Installment | Greater Than 89 Days Past Due | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	0	10
Consumer Installment | Current | Originated indirect paper
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	8,145	10,194
Consumer Installment | Current | Other consumer
Aging analysis of the Bank's real estate and consumer loans
Total allowance for credit losses on loans	$ 6,458	$ 7,095