XML 102 R86.htm IDEA: XBRL DOCUMENT
v3.20.4

Capital Requirements (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2018
Payments for repurchase of warrants |  | $ 29,005,000
Dividend payable by subsidiaries, maximum | $ 948,000,000 |

X
- Definition Represents the maximum amount of dividend the subsidiary banks could pay to the entity. + References No definition available. + Details
Name: | iboc_MaximumDividendIncomeToBeReceivedFromSubsidiaries
Namespace Prefix: | iboc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate amount paid by the entity to reacquire the right to purchase equity shares at a predetermined price, usually issued together with corporate debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsForRepurchaseOfWarrants
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration