XML 18 R47.htm IDEA: XBRL DOCUMENT
v2.3.0.15

Capital Ratios (Details) (USD $) | 1 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2009 year | Mar. 31, 2005 year | Sep. 30, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Capital Ratios |  |  |  |  |
Tier 1 capital to average total asset (leverage) ratio (as a percent) |  |  | 12.15% | 11.58% |
Risk-weighted Tier 1 capital ratio (as a percent) |  |  | 22.09% | 19.47% |
Risk-weighted total capital ratio (as a percent) |  |  | 23.34% | 20.72% |
Identified intangibles and goodwill |  |  | $ 295,972,000 |  |
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum (as a percent) |  |  | 25.00% |  |
Capital securities issued by the trust, qualifying as Tier I capital |  |  | 190,726,000 | 201,117,000 |
Length of transition period under final rule of Federal Reserve Board (in years) |  | 5 |  |  |
Percentage of trust preferred securities and certain other capital elements to Tier 1 capital, maximum (as a percent) |  |  | 25.00% |  |
Percentage of trust preferred securities to tier 1 capital for bank holding companies with significant international operations, maximum limit expected (as a percent) |  |  | 15.00% |  |
Percentage of convertible preferred securities to Tier 1 capital elements related to bank holding companies with significant international operations, maximum (as a percent) |  |  | 25.00% |  |
Extended transition period under the final rule of the Federal Reserve Board (in years) | 2 |  |  |  |
Consolidated assets required for the application of Collins amendment, minimum |  |  |  |  | $ 15,000,000,000

X
- Definition Represents capital securities issued by trust that is qualified as Tier I capital as on the reporting date. + Details
Name: | iboc_CapitalSecuritiesIssuedByTrustQualifyingAsTierOneCapital
Namespace Prefix: | iboc
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The number of years specified as the extended transition period under the final rule of the Federal Reserve Board. + Details
Name: | iboc_ExtendedTransitionPeriodUnderFederalReserveBoardFinalRule
Namespace Prefix: | iboc
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate amount of identified intangible assets and goodwill recorded in connection with acquisitions made by the entity, are deducted from the sum of core capital elements while determining capital ratios of the entity. + Details
Name: | iboc_IntangibleAssetsAndGoodwill
Namespace Prefix: | iboc
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The length of the transition period under final rule of Federal Reserve Board limiting the 25% Tier I capital to trust preferred securities and certain other elements. + Details
Name: | iboc_LengthOfTransitionPeriodUnderFederalReserveBoardFinalRule
Namespace Prefix: | iboc
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the maximum percentage of capital securities issued by the trust qualifying as Tier I capital on an aggregate basis. + Details
Name: | iboc_MaximumPercentageOfCapitalSecuritiesIssuedByTrustQualifyingAsTierOneCapital
Namespace Prefix: | iboc
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of qualifying mandatory convertible preferred securities to Tier 1 capital elements related to bank holding companies with significant international operations. + Details
Name: | iboc_MaximumPercentageOfConvertiblePreferredSecuritiesToTierOneCapitalElementsOfBankHoldingCompaniesWithSignificantInternationalOperations
Namespace Prefix: | iboc
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of the aggregate amount of trust preferred securities and certain other capital elements to Tier 1 capital elements, net of goodwill, less any associated deferred tax liability. + Details
Name: | iboc_MaximumPercentageOfTrustPreferredSecuritiesAndOtherCapitalElementsToTierOneCapital
Namespace Prefix: | iboc
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum amounts of consolidated assets required for the application of Collins amendment as per Dodd-Frank Wall Street Reform and Consumer Protection Act. + Details
Name: | iboc_MinimumConsolidatedAssetsForApplicationOfCollinsAmendment
Namespace Prefix: | iboc
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For bank holding companies with significant international operations, the expected maximum percentage of trust preferred securities to tier I capital. + Details
Name: | iboc_PercentageOfTrustPreferredSecuritiesToTierOneCapitalOfBankHoldingCompaniesWithSignificantInternationalOperationsMaximumLimitExpected
Namespace Prefix: | iboc
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BankingAndThriftAbstract
Namespace Prefix: | us-gaap
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total Capital divided by risk weighted assets as defined in the regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6918689&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Chapter 17 -Paragraph 15 -Subparagraph 3a -IssueDate 2006-05-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Chapter 17 -Paragraph 22 -IssueDate 2006-05-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -URI http://asc.fasb.org/extlink&oid=6918689&loc=d3e65071-112826 -Subparagraph (c)(2) + Details
Name: | us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier 1 Leverage Capital divided by average assets as defined in the regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Chapter 17 -Paragraph 15 -Subparagraph 3a -IssueDate 2006-05-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -URI http://asc.fasb.org/extlink&oid=6918689&loc=d3e65071-112826 -Subparagraph (c)(2) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6918689&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix: | us-gaap
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier 1 capital divided by risk weighted assets as defined by regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6918689&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Chapter 17 -Paragraph 15 -Subparagraph 3a -IssueDate 2006-05-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Chapter 17 -Paragraph 22 -IssueDate 2006-05-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -URI http://asc.fasb.org/extlink&oid=6918689&loc=d3e65071-112826 -Subparagraph (c)(2) + Details
Name: | us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant