LOANS AND ALLOWANCE FOR CREDIT LOSSES - Schedule of Past Due (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	$ 1,424,988	$ 1,411,784
Current
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	1,406,462	1,393,274
Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	5,652
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	1,608	10,816
30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	763	595
60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	492	$ 246
Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial real estate \| Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	5,337
Commercial real estate \| 30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial real estate \| 60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial real estate \| Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial and industrial \| Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	8
Commercial and industrial \| 30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial and industrial \| 60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Commercial and industrial \| Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Agricultural operating \| Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	179
Agricultural operating \| 30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans
Agricultural operating \| 60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans
Agricultural operating \| Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans
Residential mortgage \| Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	106
Residential mortgage \| 30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Residential mortgage \| 60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Residential mortgage \| Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Other consumer \| Current \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	22
Other consumer \| 30-59 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Other consumer \| 60-89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	0
Other consumer \| Greater Than 89 Days Past Due \| Entity Loan Modification Program
Financing Receivable, Past Due [Line Items]
Total allowance for credit losses on loans	$ 0