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Capital Requirements - Capital Amounts and Ratios (Details) - USD ($) $ in Thousands | Dec. 31, 2025 | Dec. 31, 2024
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Parent Company |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 3,215,422 | $ 2,893,228
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2336% | 0.2242%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 3,452,837 | $ 3,136,215
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2509 | 0.2431
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 3,289,921 | $ 2,974,881
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2391 | 0.2306
Tier 1 Capital (to Average Assets), Actual Amount | $ 3,289,921 | $ 2,974,881
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1986 | 0.1884
Parent Company | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 963,331 | $ 903,203
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 1,444,997 | $ 1,354,805
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 1,169,760 | $ 1,096,747
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 662,702 | $ 631,755
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
International Bank of Commerce Laredo |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,823,239 | $ 1,638,720
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2087% | 0.1946%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 1,932,526 | $ 1,744,057
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2212 | 0.2071
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,823,239 | $ 1,638,720
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2087 | 0.1946
Tier 1 Capital (to Average Assets), Actual Amount | $ 1,823,239 | $ 1,638,720
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1858 | 0.1767
International Bank of Commerce Laredo | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 611,605 | $ 589,359
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 567,919 | $ 547,262
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.065% | 0.065%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 917,407 | $ 884,039
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 873,721 | $ 841,942
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.10 | 0.10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 742,663 | $ 715,651
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 698,977 | $ 673,554
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.08 | 0.08
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 392,594 | $ 370,911
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 490,743 | $ 463,639
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.05 | 0.05
International Bank of Commerce Brownsville |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 633,425 | $ 240,023
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2878% | 0.2057%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 660,969 | $ 254,659
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3003 | 0.2182
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 633,425 | $ 240,023
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2878 | 0.2057
Tier 1 Capital (to Average Assets), Actual Amount | $ 633,425 | $ 240,023
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1417 | 0.1447
International Bank of Commerce Brownsville | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 154,089 | $ 81,679
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 143,083 | $ 75,845
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.065% | 0.065%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 231,134 | $ 122,519
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 220,127 | $ 116,685
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.10 | 0.10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 187,108 | $ 99,182
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 176,102 | $ 93,348
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.08 | 0.08
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 178,829 | $ 66,341
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 223,536 | $ 82,926
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.05 | 0.05
International Bank Of Commerce Oklahoma |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 243,414 | $ 554,879
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2069% | 0.2611%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 254,835 | $ 578,515
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2166 | 0.2722
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 243,414 | $ 554,879
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.2069 | 0.2611
Tier 1 Capital (to Average Assets), Actual Amount | $ 243,414 | $ 554,879
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1468 | 0.1308
International Bank Of Commerce Oklahoma | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 82,360 | $ 148,761
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 76,477 | $ 138,136
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.065% | 0.065%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 123,539 | $ 223,142
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 117,657 | $ 212,516
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.10 | 0.10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 100,008 | $ 180,639
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 94,125 | $ 170,013
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.08 | 0.08
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 66,316 | $ 169,680
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 82,896 | $ 212,100
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.05 | 0.05
Commerce Bank |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 86,658 | $ 66,932
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3163% | 0.3274%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 89,515 |
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3267 | 0.3389
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 86,658 | $ 69,278
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3163 | 0.3274
Tier 1 Capital (to Average Assets), Actual Amount | $ 86,658 | $ 66,932
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1154 | 0.1344
Commerce Bank | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 19,180 | $ 14,310
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 17,810 | $ 13,287
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.065% | 0.065%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 28,769 | $ 21,464
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 27,399 | $ 20,442
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.10 | 0.10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 23,289 | $ 17,376
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 21,920 | $ 16,354
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.08 | 0.08
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 30,039 | $ 19,917
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 37,549 | $ 24,896
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.05 | 0.05
International Bank of Commerce Zapata |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 70,163 | $ 102,200
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3263% | 0.375%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 72,573 | $ 105,090
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3375 | 0.3856
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 70,163 | $ 102,200
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 0.3263 | 0.375
Tier 1 Capital (to Average Assets), Actual Amount | $ 70,163 | $ 102,200
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 0.1343 | 0.1353
International Bank of Commerce Zapata | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 15,051 | $ 19,077
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 13,976 | $ 17,714
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.07% | 0.07%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.065% | 0.065%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 22,577 | $ 28,616
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 21,502 | $ 27,253
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.105 | 0.105
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.10 | 0.10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 18,277 | $ 23,165
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 17,202 | $ 21,802
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.085 | 0.085
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.08 | 0.08
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 20,898 | $ 30,219
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 26,123 | $ 37,774
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 0.04 | 0.04
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 0.05 | 0.05

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- Definition Amount of minimum Tier 1 risk-based capital required for capital adequacy with capital conservation buffer, as defined by regulatory framework. + References No definition available. + Details
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- Definition Amount of total capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 505 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477270/942-505-50-1 + Details
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