XML 18 R25.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Junior Subordinated Interest Deferrable Debentures (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2013
Junior Subordinated Interest Deferrable Debentures |
Junior subordinated deferrable interest debentures, major types of business trusts |
|  | Junior Subordinated Deferrable Interest Debentures |  | Repricing Frequency |  | Interest Rate |  | Interest Rate Index |  | Maturity Date |  | Optional Redemption Date(1)
|  | (In Thousands) |  |  |  |  |  |  |  |  |  |
Trust VI |  | $ | 25,774 |  | Quarterly |  | 3.74 | % | LIBOR + 3.45 |  | November 2032 |  | February 2008
Trust VII |  | 10,310 |  | Quarterly |  | 3.55 | % | LIBOR + 3.25 |  | April 2033 |  | April 2008
Trust VIII |  | 25,774 |  | Quarterly |  | 3.35 | % | LIBOR + 3.05 |  | October 2033 |  | October 2008
Trust IX |  | 41,238 |  | Quarterly |  | 1.93 | % | LIBOR + 1.62 |  | October 2036 |  | October 2011
Trust X |  | 34,021 |  | Quarterly |  | 1.95 | % | LIBOR + 1.65 |  | February 2037 |  | February 2012
Trust XI |  | 32,990 |  | Quarterly |  | 1.93 | % | LIBOR + 1.62 |  | July 2037 |  | July 2012
Trust XII |  | 20,619 |  | Quarterly |  | 1.74 | % | LIBOR + 1.45 |  | September 2037 |  | September 2012
|  | $ | 190,726 |  |  |  |  |  |  |  |  |  |
(1) The Capital Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

X
- Definition Tabular disclosure of borrowings under junior subordinated debt agreements, including restrictive covenants, collateral, interest rates and due dates, amounts due by date and amount owed in total. + References No definition available. + Details
Name: | iboc_ScheduleOfJuniorSubordinatedBorrowingsTableTextBlock
Namespace Prefix: | iboc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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