LOANS AND ALLOWANCE - Risk Grading of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	$ 2,212,810	$ 3,483,295
Fiscal year before current fiscal year	2,705,962	2,680,834
Two years before current fiscal year	2,210,224	1,843,080
Three years before current fiscal year	1,500,790	686,065
Four years before current fiscal year	553,043	385,461
Prior	958,254	828,159
Revolving loans amortized cost basis	2,126,807	2,084,096
Revolving loans converted to term	3,532	12,904
Total	12,271,422	12,003,894
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	918,136	1,094,363
Current fiscal year, writeoff	13,901
Fiscal year before current fiscal year	584,258	576,080
Fiscal year before current fiscal year, writeoff	508
Two years before current fiscal year	319,453	159,416
Two years before current fiscal year, writeoff	400
Three years before current fiscal year	105,004	131,332
Three years before current fiscal year, writeoff	5,588
Four years before current fiscal year	58,313	48,822
Four years before current fiscal year, writeoff	76
Prior	51,646	48,058
Prior, writeoff	239
Revolving loans amortized cost basis	1,454,093	1,373,714
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	50	5,341
Revolving loans converted to term, writeoff	0
Total	3,490,953	3,437,126
Total, writeoff	20,712
Commercial and industrial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	901,876	1,064,687
Fiscal year before current fiscal year	548,276	531,504
Two years before current fiscal year	296,471	141,985
Three years before current fiscal year	95,426	114,999
Four years before current fiscal year	53,498	43,136
Prior	49,094	45,310
Revolving loans amortized cost basis	1,374,146	1,302,562
Revolving loans converted to term	50	5,048
Total	3,318,837	3,249,231
Commercial and industrial loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	9,450	2,164
Fiscal year before current fiscal year	11,955	18,005
Two years before current fiscal year	6,428	11,900
Three years before current fiscal year	5,470	5,727
Four years before current fiscal year	114	1,012
Prior	897	2,181
Revolving loans amortized cost basis	28,202	27,702
Revolving loans converted to term	0	150
Total	62,516	68,841
Commercial and industrial loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	5,902	27,512
Fiscal year before current fiscal year	20,082	26,571
Two years before current fiscal year	16,554	5,531
Three years before current fiscal year	1,959	10,606
Four years before current fiscal year	4,701	4,674
Prior	1,655	567
Revolving loans amortized cost basis	48,890	43,450
Revolving loans converted to term	0	143
Total	99,743	119,054
Commercial and industrial loans | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	908
Fiscal year before current fiscal year	3,945
Two years before current fiscal year	0
Three years before current fiscal year	2,149
Four years before current fiscal year	0
Prior	0
Revolving loans amortized cost basis	2,855
Revolving loans converted to term	0
Total	9,857
Agricultural land, production and other loans to farmers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	22,555	44,910
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	39,288	37,083
Fiscal year before current fiscal year, writeoff	0
Two years before current fiscal year	33,059	36,281
Two years before current fiscal year, writeoff	0
Three years before current fiscal year	32,692	15,296
Three years before current fiscal year, writeoff	0
Four years before current fiscal year	13,819	4,127
Four years before current fiscal year, writeoff	0
Prior	26,912	30,694
Prior, writeoff	0
Revolving loans amortized cost basis	65,513	73,402
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	0	0
Revolving loans converted to term, writeoff	0
Total	233,838	241,793
Total, writeoff	0
Agricultural land, production and other loans to farmers | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	22,521	44,446
Fiscal year before current fiscal year	38,866	36,299
Two years before current fiscal year	33,059	35,791
Three years before current fiscal year	32,234	15,296
Four years before current fiscal year	13,819	3,752
Prior	26,251	28,910
Revolving loans amortized cost basis	65,513	73,402
Revolving loans converted to term	0	0
Total	232,263	237,896
Agricultural land, production and other loans to farmers | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	286
Fiscal year before current fiscal year	266	784
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	281
Prior	597	632
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	863	1,983
Agricultural land, production and other loans to farmers | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	34	178
Fiscal year before current fiscal year	156	0
Two years before current fiscal year	0	490
Three years before current fiscal year	458	0
Four years before current fiscal year	0	94
Prior	64	1,152
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	712	1,914
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	397,654	383,367
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	299,869	301,986
Fiscal year before current fiscal year, writeoff	0
Two years before current fiscal year	271,417	117,541
Two years before current fiscal year, writeoff	0
Three years before current fiscal year	35,171	11,428
Three years before current fiscal year, writeoff	0
Four years before current fiscal year	4,047	857
Four years before current fiscal year, writeoff	0
Prior	2,526	3,236
Prior, writeoff	0
Revolving loans amortized cost basis	11,577	17,167
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	0	0
Revolving loans converted to term, writeoff	0
Total	1,022,261	835,582
Total, writeoff	0
Construction | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	362,578	366,414
Fiscal year before current fiscal year	295,563	301,986
Two years before current fiscal year	266,129	117,541
Three years before current fiscal year	14,325	11,428
Four years before current fiscal year	4,047	857
Prior	2,526	3,224
Revolving loans amortized cost basis	11,577	17,167
Revolving loans converted to term	0	0
Total	956,745	818,617
Construction | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	35,063	16,922
Fiscal year before current fiscal year	424	0
Two years before current fiscal year	0	0
Three years before current fiscal year	20,846	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	56,333	16,922
Construction | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	13	31
Fiscal year before current fiscal year	3,882	0
Two years before current fiscal year	5,288	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	12
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	9,183	43
Commercial real estate, non-owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	298,116	630,708
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	562,124	615,408
Fiscal year before current fiscal year, writeoff	2
Two years before current fiscal year	541,141	596,899
Two years before current fiscal year, writeoff	0
Three years before current fiscal year	497,135	187,486
Three years before current fiscal year, writeoff	0
Four years before current fiscal year	169,203	132,847
Four years before current fiscal year, writeoff	0
Prior	260,968	209,128
Prior, writeoff	0
Revolving loans amortized cost basis	31,909	31,196
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	0	3,803
Revolving loans converted to term, writeoff	0
Total	2,360,596	2,407,475
Total, writeoff	2
Commercial real estate, non-owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	214,579	560,146
Fiscal year before current fiscal year	529,237	603,254
Two years before current fiscal year	533,207	550,605
Three years before current fiscal year	471,278	168,701
Four years before current fiscal year	142,636	116,859
Prior	225,787	190,264
Revolving loans amortized cost basis	31,615	31,196
Revolving loans converted to term	0	3,803
Total	2,148,339	2,224,828
Commercial real estate, non-owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	64,871	49,439
Fiscal year before current fiscal year	22,956	4,026
Two years before current fiscal year	7,842	38,268
Three years before current fiscal year	3,641	18,785
Four years before current fiscal year	26,567	11,546
Prior	32,842	17,992
Revolving loans amortized cost basis	47	0
Revolving loans converted to term	0	0
Total	158,766	140,056
Commercial real estate, non-owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	18,666	21,123
Fiscal year before current fiscal year	9,807	8,128
Two years before current fiscal year	92	8,026
Three years before current fiscal year	22,216	0
Four years before current fiscal year	0	4,442
Prior	2,339	872
Revolving loans amortized cost basis	247	0
Revolving loans converted to term	0	0
Total	53,367	42,591
Commercial real estate, non-owner occupied | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0
Fiscal year before current fiscal year	124
Two years before current fiscal year	0
Three years before current fiscal year	0
Four years before current fiscal year	0
Prior	0
Revolving loans amortized cost basis	0
Revolving loans converted to term	0
Total	124
Commercial real estate, owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	139,503	271,593
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	222,019	324,004
Fiscal year before current fiscal year, writeoff	0
Two years before current fiscal year	283,816	335,062
Two years before current fiscal year, writeoff	0
Three years before current fiscal year	277,729	119,104
Three years before current fiscal year, writeoff	0
Four years before current fiscal year	104,394	67,946
Four years before current fiscal year, writeoff	2
Prior	97,958	90,990
Prior, writeoff	0
Revolving loans amortized cost basis	28,288	34,451
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	0	3,378
Revolving loans converted to term, writeoff	0
Total	1,153,707	1,246,528
Total, writeoff	2
Commercial real estate, owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	119,212	260,725
Fiscal year before current fiscal year	207,077	316,665
Two years before current fiscal year	270,151	330,441
Three years before current fiscal year	269,190	114,015
Four years before current fiscal year	101,546	63,816
Prior	87,685	81,286
Revolving loans amortized cost basis	27,327	33,123
Revolving loans converted to term	0	3,378
Total	1,082,188	1,203,449
Commercial real estate, owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	5,178	7,744
Fiscal year before current fiscal year	13,603	6,125
Two years before current fiscal year	9,437	2,245
Three years before current fiscal year	6,053	3,481
Four years before current fiscal year	2,831	1,210
Prior	5,110	2,984
Revolving loans amortized cost basis	334	1,328
Revolving loans converted to term	0	0
Total	42,546	25,117
Commercial real estate, owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	15,113	3,124
Fiscal year before current fiscal year	1,339	1,214
Two years before current fiscal year	4,228	2,376
Three years before current fiscal year	2,486	1,608
Four years before current fiscal year	17	2,920
Prior	5,163	6,720
Revolving loans amortized cost basis	627	0
Revolving loans converted to term	0	0
Total	28,973	17,962
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	333,654	762,399
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	700,583	494,049
Fiscal year before current fiscal year, writeoff	42
Two years before current fiscal year	458,098	405,136
Two years before current fiscal year, writeoff	135
Three years before current fiscal year	374,931	115,738
Three years before current fiscal year, writeoff	3
Four years before current fiscal year	107,654	79,632
Four years before current fiscal year, writeoff	0
Prior	274,903	234,141
Prior, writeoff	63
Revolving loans amortized cost basis	7,497	5,459
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	65	101
Revolving loans converted to term, writeoff	0
Total	2,257,385	2,096,655
Total, writeoff	243
Residential | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	332,210	758,161
Fiscal year before current fiscal year	691,941	489,301
Two years before current fiscal year	451,830	401,353
Three years before current fiscal year	372,247	114,420
Four years before current fiscal year	105,548	77,768
Prior	265,879	229,812
Revolving loans amortized cost basis	4,878	5,365
Revolving loans converted to term	65	46
Total	2,224,598	2,076,226
Residential | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	1,087	2,839
Fiscal year before current fiscal year	5,304	2,924
Two years before current fiscal year	4,034	1,972
Three years before current fiscal year	1,710	513
Four years before current fiscal year	1,578	396
Prior	6,501	2,588
Revolving loans amortized cost basis	2,588	34
Revolving loans converted to term	0	0
Total	22,802	11,266
Residential | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	357	1,399
Fiscal year before current fiscal year	3,338	1,824
Two years before current fiscal year	2,234	1,811
Three years before current fiscal year	974	805
Four years before current fiscal year	528	1,468
Prior	2,523	1,741
Revolving loans amortized cost basis	31	60
Revolving loans converted to term	0	55
Total	9,985	9,163
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	9,338	40,768
Current fiscal year, writeoff	0
Fiscal year before current fiscal year	35,504	75,749
Fiscal year before current fiscal year, writeoff	160
Two years before current fiscal year	65,078	14,621
Two years before current fiscal year, writeoff	182
Three years before current fiscal year	12,625	1,572
Three years before current fiscal year, writeoff	149
Four years before current fiscal year	1,162	1,528
Four years before current fiscal year, writeoff	193
Prior	4,827	3,393
Prior, writeoff	1,422
Revolving loans amortized cost basis	477,999	492,720
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	2,819	281
Revolving loans converted to term, writeoff	0
Total	609,352	630,632
Total, writeoff	2,106
Home equity | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	9,155	40,768
Fiscal year before current fiscal year	34,784	75,670
Two years before current fiscal year	64,438	14,621
Three years before current fiscal year	11,511	1,572
Four years before current fiscal year	1,162	1,348
Prior	4,566	3,325
Revolving loans amortized cost basis	472,517	486,924
Revolving loans converted to term	2,065	281
Total	600,198	624,509
Home equity | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	120	0
Fiscal year before current fiscal year	720	0
Two years before current fiscal year	41	0
Three years before current fiscal year	1,114	0
Four years before current fiscal year	0	115
Prior	168	8
Revolving loans amortized cost basis	4,108	3,698
Revolving loans converted to term	371	0
Total	6,642	3,821
Home equity | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	63	0
Fiscal year before current fiscal year	0	79
Two years before current fiscal year	599	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	65
Prior	93	60
Revolving loans amortized cost basis	1,374	2,098
Revolving loans converted to term	383	0
Total	2,512	2,302
Individuals' loans for household and other personal expenditures
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	32,619	68,062
Current fiscal year, writeoff	98
Fiscal year before current fiscal year	53,248	43,773
Fiscal year before current fiscal year, writeoff	591
Two years before current fiscal year	31,525	13,105
Two years before current fiscal year, writeoff	291
Three years before current fiscal year	8,104	5,422
Three years before current fiscal year, writeoff	77
Four years before current fiscal year	2,746	5,942
Four years before current fiscal year, writeoff	57
Prior	6,583	3,800
Prior, writeoff	151
Revolving loans amortized cost basis	41,100	35,107
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	598	0
Revolving loans converted to term, writeoff	0
Total	176,523	175,211
Total, writeoff	1,265
Individuals' loans for household and other personal expenditures | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	32,590	67,883
Fiscal year before current fiscal year	52,860	43,639
Two years before current fiscal year	31,275	13,025
Three years before current fiscal year	8,070	5,389
Four years before current fiscal year	2,735	5,830
Prior	6,572	3,775
Revolving loans amortized cost basis	40,907	35,091
Revolving loans converted to term	597	0
Total	175,606	174,632
Individuals' loans for household and other personal expenditures | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	29	178
Fiscal year before current fiscal year	388	134
Two years before current fiscal year	250	77
Three years before current fiscal year	34	33
Four years before current fiscal year	11	28
Prior	11	17
Revolving loans amortized cost basis	193	16
Revolving loans converted to term	1	0
Total	917	483
Individuals' loans for household and other personal expenditures | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	1
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	3
Three years before current fiscal year	0	0
Four years before current fiscal year	0	84
Prior	0	8
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	0	96
Public finance and other commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	61,235	187,125
Current fiscal year, writeoff	13,999
Fiscal year before current fiscal year	209,069	212,702
Fiscal year before current fiscal year, writeoff	1,303
Two years before current fiscal year	206,637	165,019
Two years before current fiscal year, writeoff	1,008
Three years before current fiscal year	157,399	98,687
Three years before current fiscal year, writeoff	5,817
Four years before current fiscal year	91,705	43,760
Four years before current fiscal year, writeoff	328
Prior	231,931	204,719
Prior, writeoff	1,875
Revolving loans amortized cost basis	8,831	20,880
Revolving loans amortized cost basis, writeoff	0
Revolving loans converted to term	0	0
Revolving loans converted to term, writeoff	0
Total	966,807	932,892
Total, writeoff	24,330
Public finance and other commercial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	61,235	187,125
Fiscal year before current fiscal year	209,069	212,702
Two years before current fiscal year	206,637	165,019
Three years before current fiscal year	157,399	98,687
Four years before current fiscal year	91,705	43,760
Prior	231,931	204,719
Revolving loans amortized cost basis	8,831	20,880
Revolving loans converted to term	0	0
Total	$ 966,807	$ 932,892