LOANS AND ALLOWANCE - Risk Grading of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	$ 741,161	$ 2,870,871
Current fiscal year, charge-offs		14,338
Fiscal year before current fiscal year	2,599,008	2,546,512
Fiscal year before current fiscal year, charge-offs		4,012
Two years before current fiscal year	2,390,848	2,063,941
Two years before current fiscal year, charge-offs		1,350
Three years before current fiscal year	1,934,573	1,410,944
Three years before current fiscal year, charge-offs		5,894
Four years before current fiscal year	1,344,764	529,690
Four years before current fiscal year, charge-offs		338
Prior	1,360,363	892,018
Prior, charge-offs		2,107
Revolving loans amortized cost basis	2,092,374	2,164,828
Revolving loans amortized cost basis, charge-offs		0
Revolving loans converted to term	2,491	7,223
Revolving loans converted to term, charge-offs		0
Total	12,465,582	12,486,027
Total, charge-offs		28,039
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	373,417	1,223,491
Current fiscal year, charge-offs	740	13,973
Fiscal year before current fiscal year	1,089,919	498,757
Fiscal year before current fiscal year, charge-offs	554	2,711
Two years before current fiscal year	405,481	272,427
Two years before current fiscal year, charge-offs	45	576
Three years before current fiscal year	247,740	93,854
Three years before current fiscal year, charge-offs	71	5,665
Four years before current fiscal year	81,618	52,403
Four years before current fiscal year, charge-offs	345	78
Prior	84,174	46,773
Prior, charge-offs	76	261
Revolving loans amortized cost basis	1,440,016	1,483,039
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	0	204
Revolving loans converted to term, charge-offs	0	0
Total	3,722,365	3,670,948
Total, charge-offs	1,831	23,264
Commercial and industrial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	370,101	1,175,967
Fiscal year before current fiscal year	996,601	474,601
Two years before current fiscal year	367,993	253,148
Three years before current fiscal year	231,487	86,226
Four years before current fiscal year	75,654	47,910
Prior	79,364	45,020
Revolving loans amortized cost basis	1,341,496	1,393,756
Revolving loans converted to term	0	60
Total	3,462,696	3,476,688
Commercial and industrial loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	482	34,356
Fiscal year before current fiscal year	46,079	3,911
Two years before current fiscal year	13,757	1,546
Three years before current fiscal year	1,215	5,149
Four years before current fiscal year	4,807	2,986
Prior	2,895	241
Revolving loans amortized cost basis	59,223	45,994
Revolving loans converted to term	0	0
Total	128,458	94,183
Commercial and industrial loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	2,834	12,311
Fiscal year before current fiscal year	46,434	20,245
Two years before current fiscal year	23,731	17,733
Three years before current fiscal year	15,038	2,479
Four years before current fiscal year	1,157	1,507
Prior	1,915	1,512
Revolving loans amortized cost basis	35,069	40,449
Revolving loans converted to term	0	144
Total	126,178	96,380
Commercial and industrial loans | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	857
Fiscal year before current fiscal year	805	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving loans amortized cost basis	4,228	2,840
Revolving loans converted to term	0	0
Total	5,033	3,697
Agricultural land, production and other loans to farmers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	10,864	35,691
Fiscal year before current fiscal year	28,737	38,561
Two years before current fiscal year	37,422	31,511
Three years before current fiscal year	30,569	31,502
Four years before current fiscal year	30,715	12,995
Prior	37,337	25,620
Revolving loans amortized cost basis	58,787	87,534
Revolving loans converted to term	0	0
Total	234,431	263,414
Agricultural land, production and other loans to farmers | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	10,864	35,633
Fiscal year before current fiscal year	28,681	38,145
Two years before current fiscal year	37,013	31,511
Three years before current fiscal year	30,569	31,048
Four years before current fiscal year	30,261	12,995
Prior	37,157	25,462
Revolving loans amortized cost basis	58,787	87,534
Revolving loans converted to term	0	0
Total	233,332	262,328
Agricultural land, production and other loans to farmers | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	266
Two years before current fiscal year	266	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	146	122
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	412	388
Agricultural land, production and other loans to farmers | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	58
Fiscal year before current fiscal year	56	150
Two years before current fiscal year	143	0
Three years before current fiscal year	0	454
Four years before current fiscal year	454	0
Prior	34	36
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	687	698
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	101,472	430,923
Fiscal year before current fiscal year	350,195	271,917
Two years before current fiscal year	274,709	203,672
Three years before current fiscal year	164,316	29,218
Four years before current fiscal year	28,981	7,723
Prior	9,639	2,357
Revolving loans amortized cost basis	12,414	11,735
Revolving loans converted to term	0	0
Total	941,726	957,545
Construction | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	100,743	403,578
Fiscal year before current fiscal year	321,996	267,587
Two years before current fiscal year	267,749	198,350
Three years before current fiscal year	158,342	8,372
Four years before current fiscal year	8,135	7,723
Prior	9,639	2,357
Revolving loans amortized cost basis	12,414	11,735
Revolving loans converted to term	0	0
Total	879,018	899,702
Construction | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	729	25,894
Fiscal year before current fiscal year	25,332	0
Two years before current fiscal year	2,064	0
Three years before current fiscal year	652	20,846
Four years before current fiscal year	20,846	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	49,623	46,740
Construction | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	1,451
Fiscal year before current fiscal year	2,867	4,330
Two years before current fiscal year	4,896	5,322
Three years before current fiscal year	5,322	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	13,085	11,103
Commercial real estate, non-owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	141,655	470,118
Current fiscal year, charge-offs	0	0
Fiscal year before current fiscal year	416,555	535,962
Fiscal year before current fiscal year, charge-offs	339	66
Two years before current fiscal year	475,628	542,551
Two years before current fiscal year, charge-offs	3	0
Three years before current fiscal year	509,222	443,320
Three years before current fiscal year, charge-offs	0	0
Four years before current fiscal year	431,843	160,799
Four years before current fiscal year, charge-offs	0	0
Prior	377,480	231,061
Prior, charge-offs	0	0
Revolving loans amortized cost basis	15,977	17,028
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	0	0
Revolving loans converted to term, charge-offs	0	0
Total	2,368,360	2,400,839
Total, charge-offs	342	66
Commercial real estate, non-owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	113,217	373,378
Fiscal year before current fiscal year	345,073	504,280
Two years before current fiscal year	449,978	535,327
Three years before current fiscal year	497,967	418,553
Four years before current fiscal year	409,018	141,320
Prior	329,186	200,821
Revolving loans amortized cost basis	15,892	16,744
Revolving loans converted to term	0	0
Total	2,160,331	2,190,423
Commercial real estate, non-owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	28,438	76,382
Fiscal year before current fiscal year	45,237	21,145
Two years before current fiscal year	15,281	7,005
Three years before current fiscal year	11,039	4,531
Four years before current fiscal year	2,757	19,479
Prior	46,235	27,941
Revolving loans amortized cost basis	0	37
Revolving loans converted to term	0	0
Total	148,987	156,520
Commercial real estate, non-owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	20,358
Fiscal year before current fiscal year	14,773	10,537
Two years before current fiscal year	9,670	219
Three years before current fiscal year	216	20,236
Four years before current fiscal year	20,068	0
Prior	2,059	2,299
Revolving loans amortized cost basis	85	247
Revolving loans converted to term	0	0
Total	46,871	53,896
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	11,472
Two years before current fiscal year	699
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	12,171
Commercial real estate, owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	33,341	201,554
Current fiscal year, charge-offs	0	48
Fiscal year before current fiscal year	200,160	208,567
Fiscal year before current fiscal year, charge-offs	0	0
Two years before current fiscal year	207,718	269,848
Two years before current fiscal year, charge-offs	0	0
Three years before current fiscal year	253,730	270,527
Three years before current fiscal year, charge-offs	0	0
Four years before current fiscal year	241,467	100,388
Four years before current fiscal year, charge-offs	9	2
Prior	174,034	83,316
Prior, charge-offs	0	0
Revolving loans amortized cost basis	27,444	27,883
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	0	0
Revolving loans converted to term, charge-offs	0	0
Total	1,137,894	1,162,083
Total, charge-offs	9	50
Commercial real estate, owner occupied | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	32,088	176,750
Fiscal year before current fiscal year	176,955	199,821
Two years before current fiscal year	193,895	256,346
Three years before current fiscal year	241,834	263,522
Four years before current fiscal year	235,547	99,180
Prior	168,792	77,485
Revolving loans amortized cost basis	27,158	27,369
Revolving loans converted to term	0	0
Total	1,076,269	1,100,473
Commercial real estate, owner occupied | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	140	6,712
Fiscal year before current fiscal year	6,681	5,034
Two years before current fiscal year	10,555	9,319
Three years before current fiscal year	6,949	2,460
Four years before current fiscal year	2,618	919
Prior	2,098	2,902
Revolving loans amortized cost basis	0	514
Revolving loans converted to term	0	0
Total	29,041	27,860
Commercial real estate, owner occupied | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	1,113	18,092
Fiscal year before current fiscal year	16,524	3,712
Two years before current fiscal year	3,268	4,183
Three years before current fiscal year	4,947	4,545
Four years before current fiscal year	3,302	289
Prior	3,144	2,929
Revolving loans amortized cost basis	286	0
Revolving loans converted to term	0	0
Total	32,584	33,750
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	33,553	398,334
Current fiscal year, charge-offs	0	101
Fiscal year before current fiscal year	416,890	704,355
Fiscal year before current fiscal year, charge-offs	39	252
Two years before current fiscal year	709,137	448,226
Two years before current fiscal year, charge-offs	266	208
Three years before current fiscal year	440,696	368,420
Three years before current fiscal year, charge-offs	28	3
Four years before current fiscal year	358,766	100,585
Four years before current fiscal year, charge-offs	21	3
Prior	352,125	263,618
Prior, charge-offs	24	94
Revolving loans amortized cost basis	5,308	5,219
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	15	164
Revolving loans converted to term, charge-offs	0	0
Total	2,316,490	2,288,921
Total, charge-offs	378	661
Residential | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	33,315	395,363
Fiscal year before current fiscal year	413,735	695,056
Two years before current fiscal year	701,242	442,495
Three years before current fiscal year	435,538	365,297
Four years before current fiscal year	357,126	98,654
Prior	343,918	254,718
Revolving loans amortized cost basis	5,108	4,988
Revolving loans converted to term	15	83
Total	2,289,997	2,256,654
Residential | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	58	2,167
Fiscal year before current fiscal year	2,354	5,591
Two years before current fiscal year	4,340	3,202
Three years before current fiscal year	2,468	1,924
Four years before current fiscal year	623	1,065
Prior	4,213	4,837
Revolving loans amortized cost basis	200	200
Revolving loans converted to term	0	81
Total	14,256	19,067
Residential | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	180	804
Fiscal year before current fiscal year	801	3,708
Two years before current fiscal year	3,555	2,529
Three years before current fiscal year	2,690	1,199
Four years before current fiscal year	1,017	866
Prior	3,994	4,063
Revolving loans amortized cost basis	0	31
Revolving loans converted to term	0	0
Total	12,237	13,200
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	5,365	9,438
Current fiscal year, charge-offs	0	69
Fiscal year before current fiscal year	9,261	30,499
Fiscal year before current fiscal year, charge-offs	12	213
Two years before current fiscal year	28,691	62,318
Two years before current fiscal year, charge-offs	2	224
Three years before current fiscal year	59,921	12,176
Three years before current fiscal year, charge-offs	17	149
Four years before current fiscal year	12,233	1,107
Four years before current fiscal year, charge-offs	1	193
Prior	5,378	4,000
Prior, charge-offs	125	1,596
Revolving loans amortized cost basis	495,152	491,950
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	2,257	6,083
Revolving loans converted to term, charge-offs	0	0
Total	618,258	617,571
Total, charge-offs	157	2,444
Home equity | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	5,302	9,375
Fiscal year before current fiscal year	9,261	29,784
Two years before current fiscal year	27,980	61,591
Three years before current fiscal year	59,097	11,084
Four years before current fiscal year	11,158	1,092
Prior	5,046	3,875
Revolving loans amortized cost basis	489,371	484,330
Revolving loans converted to term	2,102	5,837
Total	609,317	606,968
Home equity | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	715
Two years before current fiscal year	711	0
Three years before current fiscal year	99	1,092
Four years before current fiscal year	1,075	15
Prior	84	2
Revolving loans amortized cost basis	4,245	5,031
Revolving loans converted to term	155	149
Total	6,369	7,004
Home equity | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	63	63
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	727
Three years before current fiscal year	725	0
Four years before current fiscal year	0	0
Prior	248	123
Revolving loans amortized cost basis	1,536	2,589
Revolving loans converted to term	0	97
Total	2,572	3,599
Individuals' loans for household and other personal expenditures
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	8,200	35,965
Current fiscal year, charge-offs	20	147
Fiscal year before current fiscal year	32,299	49,547
Fiscal year before current fiscal year, charge-offs	190	770
Two years before current fiscal year	45,250	28,525
Two years before current fiscal year, charge-offs	131	342
Three years before current fiscal year	26,091	6,795
Three years before current fiscal year, charge-offs	62	77
Four years before current fiscal year	5,399	2,071
Four years before current fiscal year, charge-offs	21	62
Prior	6,807	5,918
Prior, charge-offs	12	156
Revolving loans amortized cost basis	37,194	38,795
Revolving loans amortized cost basis, charge-offs	0	0
Revolving loans converted to term	219	772
Revolving loans converted to term, charge-offs	0	0
Total	161,459	168,388
Total, charge-offs	436	1,554
Individuals' loans for household and other personal expenditures | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	8,190	35,781
Fiscal year before current fiscal year	32,152	49,295
Two years before current fiscal year	44,959	28,387
Three years before current fiscal year	25,956	6,726
Four years before current fiscal year	5,351	2,070
Prior	6,787	5,904
Revolving loans amortized cost basis	37,110	38,619
Revolving loans converted to term	25	772
Total	160,530	167,554
Individuals' loans for household and other personal expenditures | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	10	184
Fiscal year before current fiscal year	137	246
Two years before current fiscal year	291	138
Three years before current fiscal year	135	69
Four years before current fiscal year	48	0
Prior	20	14
Revolving loans amortized cost basis	84	176
Revolving loans converted to term	194	0
Total	919	827
Individuals' loans for household and other personal expenditures | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	10	6
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	1
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total	10	7
Public finance and other commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	33,294	65,357
Current fiscal year, charge-offs	760
Fiscal year before current fiscal year	54,992	208,347
Fiscal year before current fiscal year, charge-offs	1,134
Two years before current fiscal year	206,812	204,863
Two years before current fiscal year, charge-offs	447
Three years before current fiscal year	202,288	155,132
Three years before current fiscal year, charge-offs	178
Four years before current fiscal year	153,742	91,619
Four years before current fiscal year, charge-offs	397
Prior	313,389	229,355
Prior, charge-offs	237
Revolving loans amortized cost basis	82	1,645
Revolving loans amortized cost basis, charge-offs	0
Revolving loans converted to term	0	0
Revolving loans converted to term, charge-offs	0
Total	964,599	956,318
Total, charge-offs	3,153
Public finance and other commercial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current fiscal year	33,294	65,357
Fiscal year before current fiscal year	54,992	208,347
Two years before current fiscal year	206,812	204,863
Three years before current fiscal year	202,288	155,132
Four years before current fiscal year	153,742	91,619
Prior	313,389	229,355
Revolving loans amortized cost basis	82	1,645
Revolving loans converted to term	0	0
Total	$ 964,599	$ 956,318