Loans Held-for-Investment and Allowance for Credit Losses - Schedule of Past Due Loans (Detail) - USD ($) $ in Thousands		Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 7,946,000	$ 7,914,000	$ 7,230,000
Total Loans		7,945,611	7,913,098	7,229,410
Total 90 Days Past Due Still Accruing		1,143	287	33
C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,144,000	1,177,000	1,192,000
Total Loans		1,144,429	1,176,993	1,191,516
Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		339,000	369,000	211,000
Total Loans		338,303	369,246	211,013
Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,098,000	1,055,000	922,000
Total Loans		1,098,069	1,054,603	921,773
Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		331,000	340,000	311,000
Total Loans		331,464	339,665	311,002
Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		754,000	806,000	854,000
Total Loans		753,898	805,566	853,721
Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,143,000	1,083,000	1,033,000
Total Loans		1,142,618	1,083,100	1,032,845
Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,218,000	2,196,000	1,918,000
Total Loans		2,217,740	2,196,767	1,918,573
Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		679,000	640,000	550,000
Total Loans		679,189	638,560	549,837
Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		150,000	153,000	151,000
Total Loans		149,715	153,055	151,248
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,482,732	1,546,239	1,402,529
Total 90 Days Past Due Still Accruing		45	258	33
Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,144,429	1,176,993	1,191,516
Total 90 Days Past Due Still Accruing		45	258	33
Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		338,303	369,246	211,013
Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		90,186	95,543	87,882
Total 90 Days Past Due Still Accruing				0
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		5,543,789	5,479,701	5,037,914
Total 90 Days Past Due Still Accruing		1,098	29	0
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,098,069	1,054,603	921,773
Total 90 Days Past Due Still Accruing		1,098	0
Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		331,464	339,665	311,002
Total 90 Days Past Due Still Accruing		0
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		753,898	805,566	853,721
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,142,618	1,083,100	1,032,845
Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		2,217,740	2,196,767	1,918,573
Total 90 Days Past Due Still Accruing		0	29	0
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		828,904	791,615	701,085
Total 90 Days Past Due Still Accruing		0		0
Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		679,189	638,560	549,837
Total 90 Days Past Due Still Accruing		0
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		149,715	153,055	151,248
Total 90 Days Past Due Still Accruing		0		0
15-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	46,067	32,543	37,342
15-59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	6,086	4,581	6,487
15-59 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	5,875	4,232	6,462
15-59 Days Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	211	349	25
15-59 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	1,677	917	624
15-59 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	36,793	25,681	29,045
15-59 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	10,423	5,652	9,277
15-59 Days Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	438	433	855
15-59 Days Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	276	666	1,840
15-59 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	1,485	3,151	3,269
15-59 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	24,171	15,779	13,804
15-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	1,511	1,364	1,186
15-59 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	1,307	1,227	967
15-59 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[1]	204	137	219
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		9,089	8,228	1,081
60-89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,761	3,974	250
60-89 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,761	3,938	250
60-89 Days Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		0
60-89 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		9	10	0
60-89 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,086	4,069	698
60-89 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		509	564	258
60-89 Days Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		0	1,128	7
60-89 Days Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		98		19
60-89 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		501	246	0
60-89 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,978	2,131	414
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		233	175	133
60-89 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		183	141	120
60-89 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		50	34	13
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		8,673	8,043	7,091
Greater than 90 Days [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,560	1,368	1,594
Greater than 90 Days [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,560	1,368	1,594
Greater than 90 Days [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		37	795	71
Greater than 90 Days [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		6,981	5,880	5,426
Greater than 90 Days [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,759	609	1,347
Greater than 90 Days [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		348		95
Greater than 90 Days [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,708	1,979	1,374
Greater than 90 Days [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,143	1,145	70
Greater than 90 Days [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,023	2,147	2,540
Greater than 90 Days [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		95	0	0
Greater than 90 Days [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		11	0	0
Greater than 90 Days [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		84		0
Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		63,829	48,814	45,514
Total Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		12,407	9,923	8,331
Total Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		12,196	9,538	8,306
Total Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		211	385	25
Total Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,723	1,722	695
Total Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		47,860	35,630	35,169
Total Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		12,691	6,825	10,882
Total Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		786	1,561	957
Total Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,082	2,645	3,233
Total Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,129	4,542	3,339
Total Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		29,172	20,057	16,758
Total Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,839	1,539	1,319
Total Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,501	1,368	1,087
Total Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		338	171	232
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		7,881,782	7,864,284	7,183,896
Current [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,470,325	1,536,316	1,394,198
Current [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,132,233	1,167,455	1,183,210
Current [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		338,092	368,861	210,988
Current [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		88,463	93,821	87,187
Current [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		5,495,929	5,444,071	5,002,745
Current [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,085,378	1,047,778	910,891
Current [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		330,678	338,104	310,045
Current [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		751,816	802,921	850,488
Current [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,139,489	1,078,558	1,029,506
Current [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,188,568	2,176,710	1,901,815
Current [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		827,065	790,076	699,766
Current [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		677,688	637,192	548,750
Current [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 149,377	$ 152,884	$ 151,016

[1] The Company monitors commercial, agricultural and real estate loans after such loans are 15 days past due. Consumer loans are monitored after such loans are 30 days past due.