Loans Held for Investment and Allowance for Credit Losses on Loans - Gross Loans Held for Investment by Year of Origination and Internally Assigned Credit Grades (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	$ 2,264,479	$ 2,297,658
Fiscal year before current fiscal year	1,428,113	1,023,819
Two years before current fiscal year	752,483	747,672
Three years before current fiscal year	541,762	372,852
Four years before current fiscal year	242,342	233,568
Prior	589,317	583,158
Revolving Loans Amortized Cost Basis	1,125,067	910,715
Total Loans	6,943,563	6,169,442
Farmland [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	261,518
Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	6,943,563
Real Estate [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	206,690	189,699
Fiscal year before current fiscal year	181,587	164,908
Two years before current fiscal year	134,343	136,895
Three years before current fiscal year	112,408	68,266
Four years before current fiscal year	53,126	48,048
Prior	150,482	133,071
Revolving Loans Amortized Cost Basis	67,825	34,667
Total Loans	906,461	775,554
Real Estate [Member] | Commercial Real Estate Owner Occupied [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	171,615	153,887
Fiscal year before current fiscal year	145,317	130,835
Two years before current fiscal year	106,803	113,830
Three years before current fiscal year	91,892	59,163
Four years before current fiscal year	44,086	37,647
Prior	119,755	102,438
Revolving Loans Amortized Cost Basis	53,026	25,128
Total Loans	732,494	622,928
Real Estate [Member] | Commercial Real Estate Owner Occupied [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	34,800	35,475
Fiscal year before current fiscal year	34,283	33,198
Two years before current fiscal year	27,153	21,570
Three years before current fiscal year	18,072	8,397
Four years before current fiscal year	8,528	9,936
Prior	29,077	29,191
Revolving Loans Amortized Cost Basis	14,737	9,152
Total Loans	166,650	146,919
Real Estate [Member] | Commercial Real Estate Owner Occupied [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	235
Fiscal year before current fiscal year	1,718	275
Two years before current fiscal year	387	605
Three years before current fiscal year	1,334	261
Four years before current fiscal year	332	465
Prior	1,161	1,071
Revolving Loans Amortized Cost Basis	62	62
Total Loans	5,229	2,739
Real Estate [Member] | Commercial Real Estate Owner Occupied [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	40	337
Fiscal year before current fiscal year	269	600
Two years before current fiscal year		890
Three years before current fiscal year	1,110	445
Four years before current fiscal year	180
Prior	489	371
Revolving Loans Amortized Cost Basis		325
Total Loans	2,088	2,968
Real Estate [Member] | Commercial Real Estate Non-Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	473,474	313,768
Fiscal year before current fiscal year	290,050	256,098
Two years before current fiscal year	199,599	168,595
Three years before current fiscal year	157,732	90,446
Four years before current fiscal year	48,737	57,005
Prior	138,615	155,820
Revolving Loans Amortized Cost Basis	77,100	53,592
Total Loans	1,385,307	1,095,324
Real Estate [Member] | Commercial Real Estate Non-Owner Occupied [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	350,425	252,718
Fiscal year before current fiscal year	239,477	204,892
Two years before current fiscal year	170,415	114,429
Three years before current fiscal year	108,095	51,440
Four years before current fiscal year	23,754	37,305
Prior	66,564	118,264
Revolving Loans Amortized Cost Basis	45,172	29,257
Total Loans	1,003,902	808,305
Real Estate [Member] | Commercial Real Estate Non-Owner Occupied [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	115,372	53,548
Fiscal year before current fiscal year	50,573	51,206
Two years before current fiscal year	29,031	50,912
Three years before current fiscal year	46,904	38,850
Four years before current fiscal year	24,877	19,466
Prior	70,686	36,808
Revolving Loans Amortized Cost Basis	31,928	24,335
Total Loans	369,371	275,125
Real Estate [Member] | Commercial Real Estate Non-Owner Occupied [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	7,677	7,095
Two years before current fiscal year	153	3,254
Three years before current fiscal year	2,733	121
Four years before current fiscal year	64	234
Prior	1,318	656
Total Loans	11,945	11,360
Real Estate [Member] | Commercial Real Estate Non-Owner Occupied [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year		407
Three years before current fiscal year		35
Four years before current fiscal year	42
Prior	47	92
Total Loans	89	534
Real Estate [Member] | Construction and Development Less than 60 Months [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	206,198	211,932
Fiscal year before current fiscal year	113,261	41,862
Two years before current fiscal year	41,874	70,946
Three years before current fiscal year	20,136	13,814
Four years before current fiscal year	5,115	2,774
Prior	5,866	4,691
Revolving Loans Amortized Cost Basis	88,620	69,447
Total Loans	481,070	415,466
Real Estate [Member] | Construction and Development Less than 60 Months [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	169,189	173,384
Fiscal year before current fiscal year	92,988	34,351
Two years before current fiscal year	40,187	57,729
Three years before current fiscal year	5,721	9,276
Four years before current fiscal year	3,467	1,953
Prior	5,071	4,181
Revolving Loans Amortized Cost Basis	40,474	32,294
Total Loans	357,097	313,168
Real Estate [Member] | Construction and Development Less than 60 Months [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	36,042	37,275
Fiscal year before current fiscal year	20,273	7,511
Two years before current fiscal year	1,513	13,161
Three years before current fiscal year	14,368	4,526
Four years before current fiscal year	1,648	803
Prior	774	510
Revolving Loans Amortized Cost Basis	47,988	37,153
Total Loans	122,606	100,939
Real Estate [Member] | Construction and Development Less than 60 Months [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	967	1,273
Two years before current fiscal year	141
Three years before current fiscal year		6
Prior	8
Revolving Loans Amortized Cost Basis	158
Total Loans	1,274	1,279
Real Estate [Member] | Construction and Development Less than 60 Months [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Two years before current fiscal year	33	56
Three years before current fiscal year	47	6
Four years before current fiscal year		18
Prior	13
Total Loans	93	80
Real Estate [Member] | Construction Residential Real Estate Less than 60 Months [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	251,420	221,959
Fiscal year before current fiscal year	13,986	10,350
Two years before current fiscal year	361	41
Three years before current fiscal year	18
Four years before current fiscal year		18
Prior	442	454
Revolving Loans Amortized Cost Basis	38,205	21,702
Total Loans	304,432	254,524
Real Estate [Member] | Construction Residential Real Estate Less than 60 Months [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	210,099	193,311
Fiscal year before current fiscal year	12,824	7,786
Two years before current fiscal year	259	41
Three years before current fiscal year	18
Four years before current fiscal year		18
Prior	42	29
Revolving Loans Amortized Cost Basis	36,114	16,247
Total Loans	259,356	217,432
Real Estate [Member] | Construction Residential Real Estate Less than 60 Months [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	39,689	28,170
Fiscal year before current fiscal year	1,152	2,564
Two years before current fiscal year	102
Prior	400	425
Revolving Loans Amortized Cost Basis	2,091	5,455
Total Loans	43,434	36,614
Real Estate [Member] | Construction Residential Real Estate Less than 60 Months [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	1,212	478
Total Loans	1,212	478
Real Estate [Member] | Construction Residential Real Estate Less than 60 Months [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	420
Fiscal year before current fiscal year	10
Total Loans	430
Real Estate [Member] | Residential Real Estate First Lien [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	352,634	302,129
Fiscal year before current fiscal year	244,368	202,546
Two years before current fiscal year	168,670	117,334
Three years before current fiscal year	101,339	80,738
Four years before current fiscal year	68,394	58,207
Prior	180,201	172,124
Revolving Loans Amortized Cost Basis	4,100	3,928
Total Loans	1,119,706	937,006
Real Estate [Member] | Residential Real Estate First Lien [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	304,206	256,834
Fiscal year before current fiscal year	205,277	174,718
Two years before current fiscal year	141,807	99,082
Three years before current fiscal year	85,850	64,949
Four years before current fiscal year	56,028	45,211
Prior	137,254	128,898
Revolving Loans Amortized Cost Basis	4,100	3,928
Total Loans	934,522	773,620
Real Estate [Member] | Residential Real Estate First Lien [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	46,433	44,080
Fiscal year before current fiscal year	36,877	26,073
Two years before current fiscal year	25,623	15,719
Three years before current fiscal year	13,414	12,612
Four years before current fiscal year	11,725	10,926
Prior	37,242	38,230
Total Loans	171,314	147,640
Real Estate [Member] | Residential Real Estate First Lien [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	1,940	1,151
Fiscal year before current fiscal year	1,903	1,266
Two years before current fiscal year	1,065	2,054
Three years before current fiscal year	1,689	1,930
Four years before current fiscal year	497	1,155
Prior	3,889	3,523
Total Loans	10,983	11,079
Real Estate [Member] | Residential Real Estate First Lien [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	55	64
Fiscal year before current fiscal year	311	489
Two years before current fiscal year	175	479
Three years before current fiscal year	386	1,247
Four years before current fiscal year	144	915
Prior	1,816	1,473
Total Loans	2,887	4,667
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	37,800	18,965
Fiscal year before current fiscal year	13,103	16,539
Two years before current fiscal year	12,539	10,722
Three years before current fiscal year	7,129	7,379
Four years before current fiscal year	5,084	5,710
Prior	14,611	14,981
Revolving Loans Amortized Cost Basis	108,739	86,722
Total Loans	199,005	161,018
Real Estate [Member] | Residential Real Estate All Other [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	31,762	16,376
Fiscal year before current fiscal year	11,012	13,320
Two years before current fiscal year	10,696	8,691
Three years before current fiscal year	5,458	5,609
Four years before current fiscal year	3,607	4,101
Prior	11,198	12,386
Revolving Loans Amortized Cost Basis	42,629	30,840
Total Loans	116,362	91,323
Real Estate [Member] | Residential Real Estate All Other [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	5,657	2,183
Fiscal year before current fiscal year	1,887	2,941
Two years before current fiscal year	1,744	1,919
Three years before current fiscal year	1,589	1,500
Four years before current fiscal year	1,237	895
Prior	2,574	2,202
Revolving Loans Amortized Cost Basis	64,231	55,000
Total Loans	78,919	66,640
Real Estate [Member] | Residential Real Estate All Other [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	381	250
Fiscal year before current fiscal year	186	98
Two years before current fiscal year	71	112
Three years before current fiscal year	50	232
Four years before current fiscal year	201	702
Prior	786	309
Revolving Loans Amortized Cost Basis	1,828	538
Total Loans	3,503	2,241
Real Estate [Member] | Residential Real Estate All Other [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year		156
Fiscal year before current fiscal year	18	180
Two years before current fiscal year	28
Three years before current fiscal year	32	38
Four years before current fiscal year	39	12
Prior	53	84
Revolving Loans Amortized Cost Basis	51	344
Total Loans	221	814
Real Estate [Member] | Farmland [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	66,207	68,244
Fiscal year before current fiscal year	48,213	52,318
Two years before current fiscal year	38,135	48,829
Three years before current fiscal year	27,611	21,863
Four years before current fiscal year	15,688	18,140
Prior	46,331	41,766
Revolving Loans Amortized Cost Basis	19,333	21,019
Total Loans	261,518	272,179
Real Estate [Member] | Farmland [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	47,211	47,485
Fiscal year before current fiscal year	33,771	39,216
Two years before current fiscal year	29,454	23,627
Three years before current fiscal year	18,693	15,180
Four years before current fiscal year	10,038	12,579
Prior	29,724	29,457
Revolving Loans Amortized Cost Basis	6,126	6,946
Total Loans	175,017	174,490
Real Estate [Member] | Farmland [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	16,140	16,063
Fiscal year before current fiscal year	14,294	8,702
Two years before current fiscal year	6,536	23,688
Three years before current fiscal year	8,855	5,488
Four years before current fiscal year	5,428	4,159
Prior	14,373	10,848
Revolving Loans Amortized Cost Basis	11,281	10,455
Total Loans	76,907	79,403
Real Estate [Member] | Farmland [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	2,196	3,587
Fiscal year before current fiscal year	111	4,021
Two years before current fiscal year	2,090	1,514
Three years before current fiscal year	63	74
Four years before current fiscal year	141	1,293
Prior	2,023	1,316
Revolving Loans Amortized Cost Basis	1,926	3,386
Total Loans	8,550	15,191
Real Estate [Member] | Farmland [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	660	1,109
Fiscal year before current fiscal year	37	379
Two years before current fiscal year	55
Three years before current fiscal year		1,121
Four years before current fiscal year	81	109
Prior	211	145
Revolving Loans Amortized Cost Basis		232
Total Loans	1,044	3,095
Commercial and Agricultural Non-Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	409,922	535,649
Fiscal year before current fiscal year	271,328	154,760
Two years before current fiscal year	95,450	123,160
Three years before current fiscal year	68,627	66,406
Four years before current fiscal year	33,752	36,768
Prior	48,582	56,279
Revolving Loans Amortized Cost Basis	448,714	443,071
Total Loans	1,376,375	1,416,093
Commercial and Agricultural Non-Real Estate [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	303,340	445,864
Fiscal year before current fiscal year	215,247	121,786
Two years before current fiscal year	72,246	95,379
Three years before current fiscal year	53,808	44,593
Four years before current fiscal year	15,410	32,169
Prior	42,842	43,750
Revolving Loans Amortized Cost Basis	316,942	307,361
Total Loans	1,019,835	1,090,902
Commercial and Agricultural Non-Real Estate [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	100,010	85,920
Fiscal year before current fiscal year	54,656	30,568
Two years before current fiscal year	20,423	25,097
Three years before current fiscal year	12,914	9,680
Four years before current fiscal year	16,187	2,735
Prior	3,832	10,821
Revolving Loans Amortized Cost Basis	126,503	105,700
Total Loans	334,525	270,521
Commercial and Agricultural Non-Real Estate [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	6,332	2,995
Fiscal year before current fiscal year	826	2,185
Two years before current fiscal year	1,682	1,347
Three years before current fiscal year	816	11,479
Four years before current fiscal year	1,745	1,291
Prior	797	599
Revolving Loans Amortized Cost Basis	5,070	27,716
Total Loans	17,268	47,612
Commercial and Agricultural Non-Real Estate [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	240	870
Fiscal year before current fiscal year	599	221
Two years before current fiscal year	1,099	1,337
Three years before current fiscal year	825	654
Four years before current fiscal year	410	573
Prior	1,111	1,109
Revolving Loans Amortized Cost Basis	199	2,294
Total Loans	4,483	7,058
Commercial and Agricultural Non-Real Estate [Member] | Grade 5 [Member]
Financing Receivable Recorded Investment [Line Items]
Three years before current fiscal year	264
Total Loans	264
Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	225,469	222,450
Fiscal year before current fiscal year	115,973	88,564
Two years before current fiscal year	44,259	50,662
Three years before current fiscal year	23,040	20,026
Four years before current fiscal year	7,601	6,639
Prior	3,614	3,429
Revolving Loans Amortized Cost Basis	27,083	21,600
Total Loans	447,039	413,370
Consumer Non-real Estate [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	203,335	201,893
Fiscal year before current fiscal year	104,409	80,616
Two years before current fiscal year	39,822	43,793
Three years before current fiscal year	21,076	17,587
Four years before current fiscal year	6,589	5,723
Prior	2,187	2,048
Revolving Loans Amortized Cost Basis	26,263	20,600
Total Loans	403,681	372,260
Consumer Non-real Estate [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	21,078	19,349
Fiscal year before current fiscal year	10,542	7,551
Two years before current fiscal year	3,978	6,119
Three years before current fiscal year	1,541	2,167
Four years before current fiscal year	822	816
Prior	1,351	1,342
Revolving Loans Amortized Cost Basis	816	996
Total Loans	40,128	38,340
Consumer Non-real Estate [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	827	1,146
Fiscal year before current fiscal year	671	307
Two years before current fiscal year	405	551
Three years before current fiscal year	282	203
Four years before current fiscal year	134	86
Prior	63	31
Revolving Loans Amortized Cost Basis	4	4
Total Loans	2,386	2,328
Consumer Non-real Estate [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	229	62
Fiscal year before current fiscal year	351	90
Two years before current fiscal year	54	199
Three years before current fiscal year	141	69
Four years before current fiscal year	56	14
Prior	13	8
Total Loans	844	442
Oil and Gas [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	34,665	212,863
Fiscal year before current fiscal year	136,244	35,874
Two years before current fiscal year	17,253	20,488
Three years before current fiscal year	23,722	3,914
Four years before current fiscal year	4,845	259
Prior	573	543
Revolving Loans Amortized Cost Basis	245,348	154,967
Total Loans	462,650	428,908
Oil and Gas [Member] | Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	24,938	188,072
Fiscal year before current fiscal year	125,209	26,090
Two years before current fiscal year	16,482	6,579
Three years before current fiscal year	682	1,257
Four years before current fiscal year	1,678	89
Prior	246	73
Revolving Loans Amortized Cost Basis	199,610	139,687
Total Loans	368,845	361,847
Oil and Gas [Member] | Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	7,610	17,150
Fiscal year before current fiscal year	10,668	9,774
Two years before current fiscal year	766	13,909
Three years before current fiscal year	23,040	2,657
Four years before current fiscal year	3,167	170
Prior	327	215
Revolving Loans Amortized Cost Basis	45,240	13,186
Total Loans	90,818	57,061
Oil and Gas [Member] | Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year	2,117	6,641
Fiscal year before current fiscal year	47	10
Two years before current fiscal year	5
Prior		255
Revolving Loans Amortized Cost Basis	498	2,024
Total Loans	2,667	8,930
Oil and Gas [Member] | Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Current fiscal year		1,000
Fiscal year before current fiscal year	320
Revolving Loans Amortized Cost Basis		70
Total Loans	$ 320	$ 1,070