Allowance for Credit Losses, Credit Quality and Other - Summary of Most Recent Analysis Performed, Risk Category of Loans by Class of Loans and Writeoffs (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	$ 2,197,674	$ 2,138,730
Year Two	2,138,138	3,341,500
Year Three	3,107,235	2,083,044
Year Four	1,554,947	1,132,926
Year Five	867,316	872,429
Prior	3,045,313	2,908,528
Revolving Loans Amortized Cost Basis	1,853,877	1,947,571
Total	14,764,500	14,424,728
Writeoffs, Year One	3,044	3,252
Writeoffs, Year Two	838	490
Writeoffs, Year Three	34,489	1,351
Writeoffs, Year Four	2,243	1,072
Writeoffs, Year Five	10,522	2,878
Writeoffs, Prior	7,883	6,357
Writeoffs, Revolving	4,017	655
Writeoffs, Total	63,036	16,055
Commercial real estate loans
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	1,350,313	930,022
Year Two	1,037,666	2,146,390
Year Three	1,947,209	1,262,133
Year Four	938,027	626,807
Year Five	443,400	481,164
Prior	1,920,283	1,905,250
Revolving Loans Amortized Cost Basis	863,089	816,391
Total	8,499,987	8,168,157
Commercial real estate loans \| Non-farm/non-residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	333,198	388,831
Year Two	423,332	1,150,598
Year Three	1,212,296	830,588
Year Four	785,056	491,298
Year Five	363,710	404,822
Prior	1,767,050	1,747,135
Revolving Loans Amortized Cost Basis	542,138	536,682
Total	5,426,780	5,549,954
Writeoffs, Year One	0	0
Writeoffs, Year Two	0	0
Writeoffs, Year Three	26,059	0
Writeoffs, Year Four	779	0
Writeoffs, Year Five	9,979	1,826
Writeoffs, Prior	1,220	502
Writeoffs, Revolving	95	0
Writeoffs, Total	38,132	2,328
Commercial real estate loans \| Construction/ Land Development
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	963,907	501,215
Year Two	571,039	926,208
Year Three	676,520	384,657
Year Four	115,480	88,901
Year Five	47,913	55,857
Prior	82,999	81,216
Revolving Loans Amortized Cost Basis	278,356	254,993
Total	2,736,214	2,293,047
Writeoffs, Year One	0	0
Writeoffs, Year Two	0	2
Writeoffs, Year Three	666	168
Writeoffs, Year Four	526	5
Writeoffs, Year Five	33	0
Writeoffs, Prior	0	88
Writeoffs, Revolving	212	0
Writeoffs, Total	1,437	263
Commercial real estate loans \| Agricultural
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	53,208	39,976
Year Two	43,295	69,584
Year Three	58,393	46,888
Year Four	37,491	46,608
Year Five	31,777	20,485
Prior	70,234	76,899
Revolving Loans Amortized Cost Basis	42,595	24,716
Total	336,993	325,156
Writeoffs, Year One	0	0
Writeoffs, Year Two	0	0
Writeoffs, Year Three	0	0
Writeoffs, Year Four	0	0
Writeoffs, Year Five	0	1
Writeoffs, Prior	0	6
Writeoffs, Revolving	0	0
Writeoffs, Total	0	7
Residential Real Estate \| Residential 1-4 family
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	235,119	261,784
Year Two	255,492	409,197
Year Three	422,926	300,563
Year Four	250,947	171,122
Year Five	150,113	111,327
Prior	426,755	403,729
Revolving Loans Amortized Cost Basis	215,137	186,538
Total	1,956,489	1,844,260
Writeoffs, Year One	0	0
Writeoffs, Year Two	57	29
Writeoffs, Year Three	170	28
Writeoffs, Year Four	1	73
Writeoffs, Year Five	58	13
Writeoffs, Prior	184	126
Writeoffs, Revolving	97	0
Writeoffs, Total	567	269
Residential Real Estate \| Multifamily residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	4,041	3,983
Year Two	11,699	87,012
Year Three	206,971	107,301
Year Four	49,322	108,702
Year Five	109,809	39,815
Prior	94,772	74,564
Revolving Loans Amortized Cost Basis	19,870	14,359
Total	496,484	435,736
Writeoffs, Year One	0
Writeoffs, Year Two	0
Writeoffs, Year Three	6,500
Writeoffs, Year Four	0
Writeoffs, Year Five	0
Writeoffs, Prior	0
Writeoffs, Revolving	0
Writeoffs, Total	6,500
Total real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	1,589,473	1,195,789
Year Two	1,304,857	2,642,599
Year Three	2,577,106	1,669,997
Year Four	1,238,296	906,631
Year Five	703,322	632,306
Prior	2,441,810	2,383,543
Revolving Loans Amortized Cost Basis	1,098,096	1,017,288
Total	10,952,960	10,448,153
Writeoffs, Year One	0	0
Writeoffs, Year Two	57	31
Writeoffs, Year Three	33,395	196
Writeoffs, Year Four	1,306	78
Writeoffs, Year Five	10,070	1,840
Writeoffs, Prior	1,404	722
Writeoffs, Revolving	404	0
Writeoffs, Total	46,636	2,867
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	281,031	255,930
Year Two	220,837	257,588
Year Three	216,978	216,645
Year Four	175,880	109,981
Year Five	88,720	110,406
Prior	247,924	200,071
Revolving Loans Amortized Cost Basis	2,991	3,069
Total	1,234,361	1,153,690
Writeoffs, Year One	18	0
Writeoffs, Year Two	134	51
Writeoffs, Year Three	997	44
Writeoffs, Year Four	246	98
Writeoffs, Year Five	336	63
Writeoffs, Prior	474	263
Writeoffs, Revolving	9	25
Writeoffs, Total	2,214	544
Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	259,442	619,371
Year Two	566,916	385,376
Year Three	266,801	156,919
Year Four	107,310	88,094
Year Five	50,457	114,522
Prior	308,754	276,677
Revolving Loans Amortized Cost Basis	463,095	684,032
Total	2,022,775	2,324,991
Writeoffs, Year One	0	0
Writeoffs, Year Two	576	407
Writeoffs, Year Three	97	1,110
Writeoffs, Year Four	691	894
Writeoffs, Year Five	116	911
Writeoffs, Prior	6,005	5,369
Writeoffs, Revolving	3,604	466
Writeoffs, Total	11,089	9,157
Agricultural & other
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	67,728	67,640
Year Two	45,528	55,937
Year Three	46,350	39,483
Year Four	33,461	28,220
Year Five	24,817	15,195
Prior	46,825	48,237
Revolving Loans Amortized Cost Basis	289,695	243,182
Total	554,404	497,894
Writeoffs, Year One	3,026	3,252
Writeoffs, Year Two	71	1
Writeoffs, Year Three	0	1
Writeoffs, Year Four	0	2
Writeoffs, Year Five	0	64
Writeoffs, Prior	0	3
Writeoffs, Revolving	0	164
Writeoffs, Total	3,097	3,487
Risk rating 1 \| Commercial real estate loans \| Non-farm/non-residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	232
Prior	326	116
Revolving Loans Amortized Cost Basis	68	55
Total	394	403
Risk rating 1 \| Commercial real estate loans \| Construction/ Land Development
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	10
Year Four	9	0
Year Five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	9	10
Risk rating 1 \| Commercial real estate loans \| Agricultural
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	449	0
Year Two	0	1,605
Year Three	1,393	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	1,842	1,605
Risk rating 1 \| Residential Real Estate \| Residential 1-4 family
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	91	144
Revolving Loans Amortized Cost Basis	2	2
Total	93	146
Risk rating 1 \| Residential Real Estate \| Multifamily residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	0	0
Risk rating 1 \| Total real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Year One		1,195,789
Year Two		2,642,599
Year Three		1,669,997
Year Four		906,631
Year Five		632,306
Prior		2,383,543
Revolving Loans Amortized Cost Basis		1,017,288
Total		10,448,153
Risk rating 1 \| Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	4,977	5,195
Year Two	2,256	2,952
Year Three	1,548	2,002
Year Four	789	839
Year Five	524	355
Prior	1,001	1,114
Revolving Loans Amortized Cost Basis	1,589	1,580
Total	12,684	14,037
Risk rating 1 \| Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	6,417	3,757
Year Two	833	918
Year Three	575	1,120
Year Four	417	236
Year Five	214	121
Prior	20,878	20,835
Revolving Loans Amortized Cost Basis	12,044	12,644
Total	41,378	39,631
Risk rating 1 \| Agricultural & other
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	705	408
Year Two	375	131
Year Three	120	16
Year Four	16	105
Year Five	100	0
Prior	0	2
Revolving Loans Amortized Cost Basis	993	563
Total	2,309	1,225
Risk rating 2 \| Commercial real estate loans \| Non-farm/non-residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	111
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	0	111
Risk rating 2 \| Commercial real estate loans \| Construction/ Land Development
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	100	759
Year Two	134	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	157	186
Revolving Loans Amortized Cost Basis	0	0
Total	391	945
Risk rating 2 \| Commercial real estate loans \| Agricultural
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	277	247
Year Two	238	0
Year Three	0	1,936
Year Four	1,080	0
Year Five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	1,595	2,183
Risk rating 2 \| Residential Real Estate \| Residential 1-4 family
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	259
Year Two	221	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	10	20
Revolving Loans Amortized Cost Basis	4	1
Total	235	280
Risk rating 2 \| Residential Real Estate \| Multifamily residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Total	0	0
Risk rating 2 \| Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	126
Prior	142	54
Revolving Loans Amortized Cost Basis	0	0
Total	142	180
Risk rating 2 \| Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	47	174
Year Two	117	1,293
Year Three	442	220
Year Four	66	12
Year Five	4	164
Prior	18	218
Revolving Loans Amortized Cost Basis	2,709	963
Total	3,403	3,044
Risk rating 2 \| Agricultural & other
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	153	396
Year Two	301	28
Year Three	23	1
Year Four	0	0
Year Five	0	1,181
Prior	0	100
Revolving Loans Amortized Cost Basis	2,175	693
Total	2,652	2,399
Risk rating 3 \| Commercial real estate loans \| Non-farm/non-residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	178,690	305,742
Year Two	331,274	584,860
Year Three	645,431	568,413
Year Four	512,315	243,177
Year Five	220,835	216,746
Prior	934,598	934,111
Revolving Loans Amortized Cost Basis	228,198	440,414
Total	3,051,341	3,293,463
Risk rating 3 \| Commercial real estate loans \| Construction/ Land Development
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	791,840	300,941
Year Two	397,607	499,984
Year Three	337,382	130,342
Year Four	85,069	62,134
Year Five	40,870	22,656
Prior	60,994	56,180
Revolving Loans Amortized Cost Basis	70,755	44,603
Total	1,784,517	1,116,840
Risk rating 3 \| Commercial real estate loans \| Agricultural
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	38,900	30,252
Year Two	32,890	43,291
Year Three	29,013	22,919
Year Four	15,091	25,992
Year Five	20,240	10,678
Prior	42,896	43,284
Revolving Loans Amortized Cost Basis	37,392	20,104
Total	216,422	196,520
Risk rating 3 \| Residential Real Estate \| Residential 1-4 family
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	219,885	246,462
Year Two	232,289	366,149
Year Three	370,485	241,985
Year Four	222,761	145,339
Year Five	126,372	93,751
Prior	342,594	324,569
Revolving Loans Amortized Cost Basis	120,626	122,950
Total	1,635,012	1,541,205
Risk rating 3 \| Residential Real Estate \| Multifamily residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	3,744	3,314
Year Two	11,304	9,827
Year Three	33,411	37,755
Year Four	39,828	44,407
Year Five	51,573	31,436
Prior	71,488	53,068
Revolving Loans Amortized Cost Basis	7,457	6,537
Total	218,805	186,344
Risk rating 3 \| Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	268,747	240,897
Year Two	208,277	245,543
Year Three	206,878	211,312
Year Four	173,224	108,009
Year Five	87,540	108,063
Prior	234,802	191,220
Revolving Loans Amortized Cost Basis	1,152	1,264
Total	1,180,620	1,106,308
Risk rating 3 \| Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	131,583	487,896
Year Two	509,552	272,608
Year Three	230,981	78,507
Year Four	60,652	50,340
Year Five	43,587	77,761
Prior	219,289	170,610
Revolving Loans Amortized Cost Basis	196,538	227,043
Total	1,392,182	1,364,765
Risk rating 3 \| Agricultural & other
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	33,060	52,758
Year Two	42,562	45,796
Year Three	38,428	31,378
Year Four	26,408	26,918
Year Five	24,261	3,059
Prior	31,552	43,984
Revolving Loans Amortized Cost Basis	180,103	145,419
Total	376,374	349,312
Risk rating 4 \| Commercial real estate loans \| Non-farm/non-residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	120,700	83,089
Year Two	91,233	557,540
Year Three	531,601	242,217
Year Four	267,040	224,378
Year Five	131,943	149,258
Prior	617,978	590,864
Revolving Loans Amortized Cost Basis	313,529	95,360
Total	2,074,024	1,942,706
Risk rating 4 \| Commercial real estate loans \| Construction/ Land Development
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	171,954	198,874
Year Two	173,190	417,244
Year Three	320,896	252,602
Year Four	29,010	22,713
Year Five	6,848	32,342
Prior	20,977	24,527
Revolving Loans Amortized Cost Basis	207,563	209,063
Total	930,438	1,157,365
Risk rating 4 \| Commercial real estate loans \| Agricultural
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	13,582	9,477
Year Two	10,167	24,688
Year Three	27,987	20,358
Year Four	19,765	19,532
Year Five	10,453	7,873
Prior	25,539	32,692
Revolving Loans Amortized Cost Basis	5,015	4,612
Total	112,508	119,232
Risk rating 4 \| Residential Real Estate \| Residential 1-4 family
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	14,380	14,992
Year Two	18,404	37,444
Year Three	43,419	55,406
Year Four	22,952	21,240
Year Five	19,318	13,313
Prior	69,811	67,084
Revolving Loans Amortized Cost Basis	93,464	62,356
Total	281,748	271,835
Risk rating 4 \| Residential Real Estate \| Multifamily residential
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	297	669
Year Two	395	77,185
Year Three	160,913	69,546
Year Four	8,908	64,295
Year Five	58,236	8,116
Prior	22,820	18,490
Revolving Loans Amortized Cost Basis	12,413	7,822
Total	263,982	246,123
Risk rating 4 \| Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Year One	7,232	9,597
Year Two	4,556	7,534
Year Three	4,926	2,479
Year Four	1,464	69
Year Five	161	109
Prior	5,626	6,073
Revolving Loans Amortized Cost Basis	195	214
Total	24,160	26,075

Allowance for Credit Losses, Credit Quality and Other - Summary of Most Recent Analysis Performed, Risk Category of Loans by Class of Loans and Writeoffs (Detail) - USD ($)
$ in Thousands