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Capital Requirements (Capital Amounts and Ratios) (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019
Capital Requirements |  |
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum | 25.00% |
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum | 25.00% |
Capital securities issued by the trust, qualifying as Tier I capital | $ 134,642 |
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust | 134,642 | $ 134,642
Parent Company [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,874,641 | $ 1,833,174
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 19.05% | 18.58%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 2,105,360 | $ 2,018,488
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 1,992,403 | 1,953,711
Tier 1 Capital (to Average Assets), Actual Amount | $ 1,992,403 | $ 1,953,711
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 21.40 | 20.46
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 20.25 | 19.80
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 14.92 | 16.65
Parent Company [Member] | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 688,678 | $ 690,746
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 1,033,017 | $ 1,036,118
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 836,252 | 838,762
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 534,228 | $ 469,267
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
International Bank of Commerce Laredo [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,295,437 | $ 1,268,078
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.19% | 18.23%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 1,380,685 | $ 1,315,453
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 1,295,437 | 1,268,078
Tier 1 Capital (to Average Assets), Actual Amount | $ 1,295,437 | $ 1,268,078
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 19.39 | 18.91
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.19 | 18.23
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 13.11 | 15.21
International Bank of Commerce Laredo [Member] | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 498,492 | $ 486,950
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 462,885 | $ 452,168
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 747,737 | $ 730,425
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 712,131 | 695,643
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 605,311 | 591,296
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 569,705 | 556,514
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 395,289 | 333,576
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 494,112 | $ 416,970
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 10.00 | 10.00
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 8.00 | 8.00
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 5.00 | 5.00
International Bank Of Commerce Oklahoma |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 207,339 | $ 201,202
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 17.45% | 16.91%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 218,657 | $ 206,807
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 207,339 | 201,202
Tier 1 Capital (to Average Assets), Actual Amount | $ 207,339 | $ 201,202
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.41 | 17.38
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 17.45 | 16.91
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 12.98 | 14.79
International Bank Of Commerce Oklahoma | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 83,150 | $ 83,303
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 77,211 | $ 77,353
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 124,725 | $ 124,955
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 118,786 | 119,004
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 100,968 | 101,154
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 95,029 | 95,203
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 63,879 | 54,406
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 79,848 | $ 68,007
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 10.00 | 10.00
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 8.00 | 8.00
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 5.00 | 5.00
International Bank of Commerce Brownsville [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 189,575 | $ 185,112
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 22.18% | 22.70%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 200,269 | $ 192,417
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 189,575 | 185,112
Tier 1 Capital (to Average Assets), Actual Amount | $ 189,575 | $ 185,112
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 23.43 | 23.60
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 22.18 | 22.70
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 14.55 | 17.41
International Bank of Commerce Brownsville [Member] | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 59,843 | $ 57,084
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 55,569 | $ 53,006
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 89,765 | $ 85,626
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 85,490 | 81,548
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 72,667 | 69,316
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 68,392 | 65,239
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 52,101 | 42,529
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 65,127 | $ 53,161
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 10.00 | 10.00
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 8.00 | 8.00
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 5.00 | 5.00
International Bank of Commerce Zapata [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 71,369 | $ 72,402
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 34.51% | 36.46%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 73,510 | $ 74,737
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 71,369 | 72,402
Tier 1 Capital (to Average Assets), Actual Amount | $ 71,369 | $ 72,402
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 35.55 | 37.63
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 34.51 | 36.46
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 16.52 | 19.08
International Bank of Commerce Zapata [Member] | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 14,476 | $ 13,902
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 13,442 | $ 12,909
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 21,714 | $ 20,853
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 20,680 | 19,860
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 17,578 | 16,881
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 16,544 | 15,888
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 17,277 | 15,179
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 21,596 | $ 18,974
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 10.00 | 10.00
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 8.00 | 8.00
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 5.00 | 5.00
Commerce Bank [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 93,426 | $ 91,239
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 35.64% | 34.83%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 96,240 |
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 93,426 | $ 93,396
Tier 1 Capital (to Average Assets), Actual Amount | $ 93,426 | $ 91,239
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 36.72 | 35.65
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 35.64 | 34.83
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 16.69 | 18.18
Commerce Bank [Member] | Minimum [Member] |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 18,347 | $ 18,336
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 17,037 | $ 17,026
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 27,521 | $ 27,504
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 26,210 | 26,195
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 22,279 | 22,265
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 20,968 | 20,956
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 22,394 | 20,073
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 27,993 | $ 25,091
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.500 | 10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 10.00 | 10.00
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.500 | 8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 8.00 | 8.00
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00 | 4.00
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent) | 5.00 | 5.00

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