LOANS AND ALLOWANCE - Past Due Aging of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans	$ 12,271,422	$ 12,003,894
Loans > 90 Days or More Past Due And Accruing	89	1,737
Current
Financing Receivable, Past Due [Line Items]
Loans	12,195,139	11,952,887
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	25,844	29,051
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	18,661	5,935
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	31,778	16,021
Commercial and industrial loans
Financing Receivable, Past Due [Line Items]
Loans	3,490,953	3,437,126
Loans > 90 Days or More Past Due And Accruing	12	1,147
Commercial and industrial loans | Current
Financing Receivable, Past Due [Line Items]
Loans	3,474,368	3,429,314
Commercial and industrial loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,005	4,904
Commercial and industrial loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,224	434
Commercial and industrial loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	9,356	2,474
Agricultural land, production and other loans to farmers
Financing Receivable, Past Due [Line Items]
Loans	233,838	241,793
Loans > 90 Days or More Past Due And Accruing	0	0
Agricultural land, production and other loans to farmers | Current
Financing Receivable, Past Due [Line Items]
Loans	233,811	241,739
Agricultural land, production and other loans to farmers | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	0
Agricultural land, production and other loans to farmers | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	0
Agricultural land, production and other loans to farmers | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	27	54
Construction
Financing Receivable, Past Due [Line Items]
Loans	1,022,261	835,582
Loans > 90 Days or More Past Due And Accruing	0	0
Construction | Current
Financing Receivable, Past Due [Line Items]
Loans	1,021,537	832,716
Construction | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	300	2,436
Construction | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	424	418
Construction | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	12
Commercial real estate, non-owner occupied
Financing Receivable, Past Due [Line Items]
Loans	2,360,596	2,407,475
Loans > 90 Days or More Past Due And Accruing	0	264
Commercial real estate, non-owner occupied | Current
Financing Receivable, Past Due [Line Items]
Loans	2,343,002	2,395,495
Commercial real estate, non-owner occupied | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,603	5,946
Commercial real estate, non-owner occupied | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,913	881
Commercial real estate, non-owner occupied | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	11,078	5,153
Commercial real estate, owner occupied
Financing Receivable, Past Due [Line Items]
Loans	1,153,707	1,246,528
Loans > 90 Days or More Past Due And Accruing	0	0
Commercial real estate, owner occupied | Current
Financing Receivable, Past Due [Line Items]
Loans	1,150,029	1,241,714
Commercial real estate, owner occupied | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,368	4,495
Commercial real estate, owner occupied | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,225	0
Commercial real estate, owner occupied | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	85	319
Residential
Financing Receivable, Past Due [Line Items]
Loans	2,257,385	2,096,655
Loans > 90 Days or More Past Due And Accruing	39	0
Residential | Current
Financing Receivable, Past Due [Line Items]
Loans	2,227,184	2,079,959
Residential | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,884	8,607
Residential | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,405	2,278
Residential | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	8,912	5,811
Home equity
Financing Receivable, Past Due [Line Items]
Loans	609,352	630,632
Loans > 90 Days or More Past Due And Accruing	38	326
Home equity | Current
Financing Receivable, Past Due [Line Items]
Loans	602,829	624,543
Home equity | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,878	2,206
Home equity | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,325	1,782
Home equity | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,320	2,101
Individuals' loans for household and other personal expenditures
Financing Receivable, Past Due [Line Items]
Loans	176,523	175,211
Loans > 90 Days or More Past Due And Accruing	0	0
Individuals' loans for household and other personal expenditures | Current
Financing Receivable, Past Due [Line Items]
Loans	175,605	174,629
Individuals' loans for household and other personal expenditures | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	773	343
Individuals' loans for household and other personal expenditures | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	145	142
Individuals' loans for household and other personal expenditures | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	97
Public finance and other commercial loans
Financing Receivable, Past Due [Line Items]
Loans	966,807	932,892
Loans > 90 Days or More Past Due And Accruing	0	0
Public finance and other commercial loans | Current
Financing Receivable, Past Due [Line Items]
Loans	966,774	932,778
Public finance and other commercial loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	33	114
Public finance and other commercial loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	0
Public finance and other commercial loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans	$ 0	$ 0