NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Impact of ASU 2016-13 Adoption (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Jan. 01, 2023	Dec. 31, 2022	Jun. 30, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans	$ 1,424,988		$ 1,411,784
Allowance for credit losses on unfunded commitments	(23,164)		(17,939)	$ (16,825)
Loans receivable, net	$ 1,401,824		1,393,845
Commercial/Agricultural Real Estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on unfunded commitments				(13,366)
C&I/Agricultural operating
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on unfunded commitments				(1,961)
Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on unfunded commitments				(520)
Consumer Installment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on unfunded commitments				(152)
Unallocated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on unfunded commitments				$ (826)
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		$ 22,645
Allowance for credit losses on unfunded commitments		1,537
Loans receivable, net		24,182
Accounting Standards Update 2016-13 \| Commercial/Agricultural Real Estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		18,595
Accounting Standards Update 2016-13 \| C&I/Agricultural operating
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		1,987
Accounting Standards Update 2016-13 \| Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		1,718
Accounting Standards Update 2016-13 \| Consumer Installment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		345
Accounting Standards Update 2016-13 \| Unallocated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans		$ 0
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			17,939
Allowance for credit losses on unfunded commitments			0
Loans receivable, net			17,939
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13 \| Commercial/Agricultural Real Estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			14,085
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13 \| C&I/Agricultural operating
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			2,318
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13 \| Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			599
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13 \| Consumer Installment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			129
Cumulative Effect, Period of Adoption, Adjusted Balance \| Accounting Standards Update 2016-13 \| Unallocated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			808
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			4,706
Allowance for credit losses on unfunded commitments			1,537
Loans receivable, net			6,243
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13 \| Commercial/Agricultural Real Estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			4,510
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13 \| C&I/Agricultural operating
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			(331)
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13 \| Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			1,119
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13 \| Consumer Installment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			216
Cumulative change in accounting principal for adoption \| Accounting Standards Update 2016-13 \| Unallocated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses on loans			$ (808)