XML 31 R76.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Junior Subordinated Interest Deferrable Debentures (Details 2) (USD $) In Thousands, unless otherwise specified |  |  | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2011 Trust VI | Dec. 31, 2011 Trust VII | Dec. 31, 2011 Trust VIII | Dec. 31, 2011 Trust IX | Dec. 31, 2011 Trust X Y | Dec. 31, 2011 Trust XI Y | Dec. 31, 2011 Trust XII Y
Junior subordinated deferrable interest debentures, major types of business trusts |  |  |  |  |  |  |  |  |
Junior subordinated deferrable interest debentures | $ 190,726 | $ 201,117 | $ 25,774 | $ 10,310 | $ 25,774 | $ 41,238 | $ 34,021 | $ 32,990 | $ 20,619
Interest rate (as a percent) |  |  | 3.91% | 3.68% | 3.45% | 1.99% | 6.66% | 6.82% | 6.85%
Interest rate index |  |  | LIBOR | LIBOR | LIBOR | LIBOR | FIXED for first 5 years | FIXED for first 5 years | FIXED for first 5 years
Spread on interest rate index (as a percent) |  |  | 3.45% | 3.25% | 3.05% | 1.62% |  |  |
Interest rate index, reference rate, after five years |  |  |  |  |  |  | LIBOR | LIBOR | LIBOR
Interest rate index, percentage on reference rate, after five years |  |  |  |  |  |  | 1.65% | 1.62% | 1.45%
Initial period of accrual of interest at fixed rate (in years) |  |  |  |  |  |  | 5 | 5 | 5

X
- Definition The percentage points added to the reference rate to compute the variable rate on the debt instrument after five years. + References No definition available. + Details
Name: | iboc_DebtInstrumentBasisSpreadOnVariableRateAfterFiveYears
Namespace Prefix: | iboc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The reference rate for the variable rate of the debt instrument after five years. + References No definition available. + Details
Name: | iboc_DebtInstrumentDescriptionOfVariableRateBasisAfterFiveYears
Namespace Prefix: | iboc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the period during which the business trust accrues interest at a fixed rate for debt instrument. + References No definition available. + Details
Name: | iboc_InitialPeriodOfAccrualOfInterestAtFixedRate
Namespace Prefix: | iboc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The average effective interest rate during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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 SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateTerms
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant