Loans Held for Investment and Allowance for Loan Losses - Schedule of Past Due Loans (Detail) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 6,778,000	$ 6,442,000	$ 5,878,000
Total Loans		6,777,570	6,441,868	5,878,582
Total 90 Days Past Due Still Accruing		552	0	22
C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,022,000	917,000	840,000
Total Loans		1,021,863	917,317	839,928
Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		216,000	221,000	201,000
Total Loans		215,977	221,090	200,577
Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		915,000	960,000	929,000
Total Loans		915,221	959,426	928,644
Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		336,000	306,000	250,000
Total Loans		335,644	306,322	250,028
Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		811,000	732,000	636,000
Total Loans		811,347	732,089	636,432
Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,012,000	954,000	910,000
Total Loans		1,011,511	954,400	909,899
Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,699,000	1,576,000	1,412,000
Total Loans		1,698,679	1,575,758	1,412,125
Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		535,000	551,000	468,000
Total Loans		534,603	550,635	468,147
Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		150,000	148,000	142,000
Total Loans		150,693	147,884	142,382
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,237,840	1,138,407	1,040,505
Total 90 Days Past Due Still Accruing		3
Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	[1]	1,021,863	917,317	839,928
Total 90 Days Past Due Still Accruing		3
Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		215,977	221,090	200,577
Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		82,032	76,947	90,420
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		4,772,402	4,527,995	4,137,128
Total 90 Days Past Due Still Accruing		520		2
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		915,221	959,426	928,644
Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		335,644	306,322	250,028
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		811,347	732,089	636,432
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,011,511	954,400	909,899
Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		1,698,679	1,575,758	1,412,125
Total 90 Days Past Due Still Accruing		520		2
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		685,296	698,519	610,529
Total 90 Days Past Due Still Accruing		29		20
Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		534,603	550,635	468,147
Total 90 Days Past Due Still Accruing				14
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		150,693	147,884	142,382
Total 90 Days Past Due Still Accruing		29		6
15-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	32,420	20,806	17,988
15-59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	3,949	4,000	3,240
15-59 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	3,734	3,924	3,240
15-59 Days Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	215	76	0
15-59 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	580	243	432
15-59 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	27,182	15,734	13,863
15-59 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	14,390	3,751	2,841
15-59 Days Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	776	668	1,005
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	[2]	1,395	1,444	569
15-59 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	3,356	1,151	4,061
15-59 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	7,265	8,720	5,387
15-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	709	829	453
15-59 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	574	779	292
15-59 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	[2]	135	50	161
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		10,177	1,977	4,159
60-89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		722	1,080	2,704
60-89 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		722	297	2,704
60-89 Days Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due			783
60-89 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,024		30
60-89 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		8,295	867	1,321
60-89 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,062		734
60-89 Days Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		205
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	[2]		160
60-89 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,818	0	495
60-89 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,210	707	92
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		136	30	104
60-89 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		118	30	104
60-89 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		18	0
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		6,406	2,087	3,529
Greater than 90 Days [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,651	1,646	1,470
Greater than 90 Days [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,651	1,646	1,470
Greater than 90 Days [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		15		27
Greater than 90 Days [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,661	441	1,995
Greater than 90 Days [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due			175	0
Greater than 90 Days [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		372		0
Greater than 90 Days [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,988		107
Greater than 90 Days [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due				1,292
Greater than 90 Days [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,301	266	596
Greater than 90 Days [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		79		37
Greater than 90 Days [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		14		30
Greater than 90 Days [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		65		7
Total Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		49,003	24,870	25,676
Total Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		6,322	6,726	7,414
Total Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		6,107	5,867	7,414
Total Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		215	859	0
Total Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,619	243	489
Total Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		40,138	17,042	17,179
Total Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		16,452	3,926	3,575
Total Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,353	668	1,005
Total Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,383	1,604	676
Total Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		7,174	1,151	5,848
Total Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		10,776	9,693	6,075
Total Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		924	859	594
Total Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		706	809	426
Total Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		218	50	168
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		6,728,567	6,416,998	5,852,906
Current [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,231,518	1,131,681	1,033,091
Current [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,015,756	911,450	832,514
Current [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		215,762	220,231	200,577
Current [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		80,413	76,704	89,931
Current [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,732,264	4,510,953	4,119,949
Current [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		898,769	955,500	925,069
Current [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		334,291	305,654	249,023
Current [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		806,964	730,485	635,756
Current [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,004,337	953,249	904,051
Current [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,687,903	1,566,065	1,406,050
Current [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		684,372	697,660	609,935
Current [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		533,897	549,826	467,721
Current [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 150,475	$ 147,834	$ 142,214

[1] All disclosures for the C&I loan segment include PPP loan balances, net of deferred fees and costs, as disclosed on the face of the consolidated balance sheet.

[2] 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.