XML 23 R43.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Other Borrowed Funds (Details) (USD $) In Thousands, unless otherwise specified | 9 Months Ended |
--- | --- | ---
Sep. 30, 2012 | Dec. 31, 2011
Other Borrowed Funds |  |
Other borrowed funds | $ 615,061 | $ 494,161
Percentage of decrease in other borrowed funds | 24.50% |

X
- Details
Name: | iboc_OtherBorrowedFundsDisclosureAbstract
Namespace Prefix: | iboc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage change in other borrowed funds. Borrowed funds primarily consist of short and long term borrowings from the Federal Home Loan Bank. + References No definition available. + Details
Name: | iboc_PercentageOfAdvancesFromFederalHomeLoanBanksIncreaseDecrease
Namespace Prefix: | iboc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Section 563c.102 -Paragraph 18 -Chapter V -Subsection I -LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It 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and Accounting Guide (AAG) -Number AAG-DEP -Paragraph 37 -IssueDate 2006-05-01 -Chapter 15 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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. + Details
Name: | us-gaap_AdvancesFromFederalHomeLoanBanks
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant