LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Composition of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 13,591,174	$ 12,854,359
Commercial and industrial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	4,604,895	4,114,292
Agricultural land, production and other loans to farmers
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	275,817	256,312
Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	789,021	792,144
Commercial real estate, non-owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	2,304,889	2,274,016
Commercial real estate, owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	1,232,117	1,157,944
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	2,412,783	2,374,729
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	687,021	659,811
Individuals' loans for household and other personal expenditures
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	138,703	166,028
Public finance and other commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 1,145,928	$ 1,059,083