XML 59 R5.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Consolidated Statements of Income (Parenthetical) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2012 | Jun. 30, 2011 | Jun. 30, 2012 | Jun. 30, 2011
Consolidated Statements of Income |  |  |  |
Impairment charges, other-than-temporary impairment charges | $ (301) | $ (523) | $ (254) | $ (420)
Impairment charges, other comprehensive income | $ 1,349 | $ 941 | $ 1,055 | $ 640

X
- Definition The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of the amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting. + References No definition available. + Details
Name: | iboc_OtherThanTemporaryImpairmentLossesInvestmentPortionRecognizedInEarningsNet
Namespace Prefix: | iboc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition This element represents Other Comprehensive Income or Loss, Before Tax, for the period. The pretax revenues, expenses, gains, and losses that under generally accepted accounting principles are included in comprehensive income, but excluded from net income. Includes the entity's proportionate share of an investee's equity adjustments for other comprehensive income. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph e -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 FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 22, 24, 121 -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 323 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33775-111570 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossBeforeTaxPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration