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Loans Held-for-Investment and Allowance for Credit Losses - Schedule of Past Due Loans (Detail) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024 | Sep. 30, 2024
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Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | $ 8,244,000 | $ 7,914,000 | $ 7,724,000
Total Loans |  | 8,243,625 | 7,913,098 | 7,723,191
Total 90 Days Past Due Still Accruing |  | 151 | 287 | 504
C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,175,000 | 1,177,000 | 1,176,000
Total Loans |  | 1,174,770 | 1,176,993 | 1,175,774
Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 348,000 | 369,000 | 334,000
Total Loans |  | 347,559 | 369,246 | 333,732
Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,215,000 | 1,055,000 | 1,014,000
Total Loans |  | 1,214,649 | 1,054,603 | 1,013,810
Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 323,000 | 340,000 | 316,000
Total Loans |  | 322,710 | 339,665 | 315,720
Non-Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 802,000 | 806,000 | 826,000
Total Loans |  | 802,675 | 805,566 | 825,928
Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,119,000 | 1,083,000 | 1,087,000
Total Loans |  | 1,119,425 | 1,083,100 | 1,086,750
Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 2,309,000 | 2,196,000 | 2,112,000
Total Loans |  | 2,308,708 | 2,196,767 | 2,112,196
Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 718,000 | 640,000 | 618,000
Total Loans |  | 718,501 | 638,560 | 618,103
Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 146,000 | 153,000 | 158,000
Total Loans |  | 145,808 | 153,055 | 157,909
Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 1,522,329 | 1,546,239 | 1,509,506
Total 90 Days Past Due Still Accruing |  | 8 | 258 | 224
Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 1,174,770 | 1,176,993 | 1,175,774
Total 90 Days Past Due Still Accruing |  | 8 | 258 | 224
Commercial [Member] | Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 347,559 | 369,246 | 333,732
Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 88,820 | 95,543 | 83,269
Total 90 Days Past Due Still Accruing |  | 0 |  | 0
Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 5,768,167 | 5,479,701 | 5,354,404
Total 90 Days Past Due Still Accruing |  | 143 | 29 | 280
Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 1,214,649 | 1,054,603 | 1,013,810
Total 90 Days Past Due Still Accruing |  |  | 0 | 245
Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 322,710 | 339,665 | 315,720
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 |  | 802,675 | 805,566 | 825,928
Real Estate [Member] | Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 1,119,425 | 1,083,100 | 1,086,750
Total 90 Days Past Due Still Accruing |  | 0 |  |
Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 2,308,708 | 2,196,767 | 2,112,196
Total 90 Days Past Due Still Accruing |  | 143 | 29 | 35
Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 864,309 | 791,615 | 776,012
Total 90 Days Past Due Still Accruing |  | 0 |  | 0
Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 718,501 | 638,560 | 618,103
Total 90 Days Past Due Still Accruing |  |  |  | 0
Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Loans |  | 145,808 | 153,055 | 157,909
Total 90 Days Past Due Still Accruing |  |  |  | 0
15-59 Days Past Due [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 33,563 | 32,543 | 37,161
15-59 Days Past Due [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 3,538 | 4,581 | 3,570
15-59 Days Past Due [Member] | Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 2,559 | 4,232 | 3,570
15-59 Days Past Due [Member] | Commercial [Member] | Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 979 | 349 | 0
15-59 Days Past Due [Member] | Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 101 | 917 | 192
15-59 Days Past Due [Member] | Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 28,908 | 25,681 | 32,215
15-59 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 6,930 | 5,652 | 9,116
15-59 Days Past Due [Member] | Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 610 | 433 | 777
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] | 1,239 | 666 | 203
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] | 1,979 | 3,151 | 4,045
15-59 Days Past Due [Member] | Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 18,150 | 15,779 | 18,074
15-59 Days Past Due [Member] | Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 1,016 | 1,364 | 1,184
15-59 Days Past Due [Member] | Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 776 | 1,227 | 964
15-59 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due | [1] | 240 | 137 | 220
60-89 Days Past Due [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 5,000 | 8,228 | 4,180
60-89 Days Past Due [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 551 | 3,974 | 672
60-89 Days Past Due [Member] | Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 500 | 3,938 | 672
60-89 Days Past Due [Member] | Commercial [Member] | Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 51 | 36 |
60-89 Days Past Due [Member] | Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 274 | 10 | 134
60-89 Days Past Due [Member] | Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 3,985 | 4,069 | 3,083
60-89 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 612 | 564 | 155
60-89 Days Past Due [Member] | Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 32 | 1,128 | 0
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 |  | 156 |  | 87
60-89 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 260 | 246 | 403
60-89 Days Past Due [Member] | Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 2,925 | 2,131 | 2,438
60-89 Days Past Due [Member] | Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 190 | 175 | 291
60-89 Days Past Due [Member] | Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 174 | 141 | 79
60-89 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 16 | 34 | 212
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 6,691 | 8,043 | 8,263
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,072 | 1,368 | 1,261
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,072 | 1,368 | 1,261
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  |  | 795 | 1,617
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 4,991 | 5,880 | 5,342
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 826 | 609 | 911
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 86 |  | 0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 0 | 1,979 | 2,682
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,501 | 1,145 | 1,234
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 2,578 | 2,147 | 515
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 44 | 0 | 43
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 0 | 0 | 43
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 44 |  |
Total Past Due [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 45,254 | 48,814 | 49,604
Total Past Due [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 5,161 | 9,923 | 5,503
Total Past Due [Member] | Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 4,131 | 9,538 | 5,503
Total Past Due [Member] | Commercial [Member] | Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,030 | 385 | 0
Total Past Due [Member] | Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 959 | 1,722 | 1,943
Total Past Due [Member] | Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 37,884 | 35,630 | 40,640
Total Past Due [Member] | Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 8,368 | 6,825 | 10,182
Total Past Due [Member] | Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 728 | 1,561 | 777
Total Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,395 | 2,645 | 2,972
Total Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 3,740 | 4,542 | 5,682
Total Past Due [Member] | Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 23,653 | 20,057 | 21,027
Total Past Due [Member] | Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,250 | 1,539 | 1,518
Total Past Due [Member] | Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 950 | 1,368 | 1,086
Total Past Due [Member] | Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 300 | 171 | 432
Current [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 8,198,371 | 7,864,284 | 7,673,587
Current [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,517,168 | 1,536,316 | 1,504,003
Current [Member] | Commercial [Member] | C&I [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,170,639 | 1,167,455 | 1,170,271
Current [Member] | Commercial [Member] | Municipal [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 346,529 | 368,861 | 333,732
Current [Member] | Agriculture [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 87,861 | 93,821 | 81,326
Current [Member] | Real Estate [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 5,730,283 | 5,444,071 | 5,313,764
Current [Member] | Real Estate [Member] | Construction & Development [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,206,281 | 1,047,778 | 1,003,628
Current [Member] | Real Estate [Member] | Farm [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 321,982 | 338,104 | 314,943
Current [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 801,280 | 802,921 | 822,956
Current [Member] | Real Estate [Member] | Owner Occupied CRE [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 1,115,685 | 1,078,558 | 1,081,068
Current [Member] | Real Estate [Member] | Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 2,285,055 | 2,176,710 | 2,091,169
Current [Member] | Consumer [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 863,059 | 790,076 | 774,494
Current [Member] | Consumer [Member] | Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | 717,551 | 637,192 | 617,017
Current [Member] | Consumer [Member] | Non-Auto [Member] |  |  |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |  |  |
Total Past Due |  | $ 145,508 | $ 152,884 | $ 157,477
[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.

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- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreement. + References No definition available. + Details
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- Definition Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-7 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 80 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-80 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-16 + Details
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