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Capital Requirements (Capital Amounts and Ratios) (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Parent Company |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,833,174 | $ 1,711,682
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.58% | 17.55%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 2,018,488 | $ 1,925,905
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 1,953,711 | 1,859,536
Tier 1 Capital (to Average Assets), Actual Amount | $ 1,953,711 | $ 1,859,536
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 20.46% | 19.74%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 19.80% | 19.06%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 16.65% | 15.87%
Parent Company | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 690,746 | $ 621,850
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 1,036,118 | $ 963,258
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 838,762 | 768,168
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | $ 469,267 | $ 468,593
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 8.50% | 7.875%
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent) | 4.00% | 4.00%
International Bank of Commerce, Laredo |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 1,268,078 | $ 1,201,462
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.23% | 17.24%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 1,315,453 | $ 1,248,107
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 1,268,078 | 1,201,462
Tier 1 Capital (to Average Assets), Actual Amount | $ 1,268,078 | $ 1,201,462
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.91% | 17.91%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 18.23% | 17.24%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 15.21% | 14.45%
International Bank of Commerce, Laredo | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 486,950 | $ 444,207
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 452,168 | $ 452,917
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
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 | $ 730,425 | $ 688,086
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 695,643 | 696,796
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 591,296 | 548,727
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 556,514 | 557,437
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 333,576 | 332,507
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 416,970 | $ 415,634
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
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) | 8.50% | 7.875%
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 | $ 201,202 | $ 188,997
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 16.91% | 13.95%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 206,807 | $ 198,293
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 201,202 | 188,997
Tier 1 Capital (to Average Assets), Actual Amount | $ 201,202 | $ 188,997
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 17.38% | 14.64%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 16.91% | 13.95%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 14.79% | 12.53%
International Bank Of Commerce Oklahoma | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 83,303 | $ 86,344
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 77,353 | $ 88,037
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
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 | $ 124,955 | $ 133,749
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 119,004 | 135,442
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 101,154 | 106,660
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 95,203 | 108,354
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 54,406 | 60,344
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 68,007 | $ 75,430
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
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) | 8.50% | 7.875%
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 |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 185,112 | $ 177,456
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 22.70% | 24.73%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 192,417 | $ 183,554
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 185,112 | 177,456
Tier 1 Capital (to Average Assets), Actual Amount | $ 185,112 | $ 177,456
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 23.60% | 25.58%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 22.70% | 24.73%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 17.41% | 17.25%
International Bank of Commerce, Brownsville | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 57,084 | $ 45,741
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 53,006 | $ 46,638
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
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 | $ 85,626 | $ 70,854
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 81,548 | 71,750
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 69,316 | 56,503
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 65,239 | 57,400
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 42,529 | 41,144
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 53,161 | $ 51,430
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
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) | 8.50% | 7.875%
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 |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 72,402 | $ 70,984
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 36.46% | 30.77%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 74,737 | $ 73,726
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 72,402 | 70,984
Tier 1 Capital (to Average Assets), Actual Amount | $ 72,402 | $ 70,984
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 37.63% | 31.96%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 36.46% | 30.77%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 19.08% | 16.22%
International Bank of Commerce, Zapata | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 13,902 | $ 14,707
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 12,909 | $ 14,996
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
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 | $ 20,853 | $ 22,782
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 19,860 | 23,070
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 16,881 | 18,168
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 15,888 | 18,456
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 15,179 | 17,507
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 18,974 | $ 21,884
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
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) | 8.50% | 7.875%
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 |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount | $ 91,239 | $ 89,305
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 34.83% | 32.95%
Total Capital (to Risk Weighted Assets), Actual Amount | $ 93,396 |
Tier 1 Capital (to Risk Weighted Assets), Actual Amount | 91,239 | $ 90,894
Tier 1 Capital (to Average Assets), Actual Amount | $ 91,239 | $ 89,305
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 35.65% | 33.54%
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent) | 34.83% | 32.95%
Tier 1 capital (to Average Assets), Actual Ratio (as a percent) | 18.18% | 15.53%
Commerce Bank | Minimum |  |
Capital Requirements |  |
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | $ 18,336 | $ 17,276
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 17,026 | $ 17,615
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 7.00% | 6.375%
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 | $ 27,504 | $ 26,761
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 26,195 | 27,100
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount | 22,265 | 21,341
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | 20,956 | 21,680
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount | 20,073 | 23,000
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount | $ 25,091 | $ 28,750
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent) | 10.50% | 9.875%
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) | 8.50% | 7.875%
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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- Definition Percentage of Common Equity Tier 1 capital ratio (Common Equity Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. + References No definition available. + Details
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- Definition The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826 + Details
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- Definition The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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- Definition Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as well-capitalized under regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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