XML 29 R31.htm IDEA: XBRL DOCUMENT v2.4.1.9

Loans (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Summary of loans, by loan type
Total loans	$ 5,778,742us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome	$ 5,679,245us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Commercial, financial and agricultural
Summary of loans, by loan type
Total loans	3,094,522us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_LoansReceivableCommercialFinancialAndAgriculturalMember	3,107,584us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_LoansReceivableCommercialFinancialAndAgriculturalMember
Real estate - mortgage
Summary of loans, by loan type
Total loans	916,938us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ResidentialMortgageMember	910,326us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ResidentialMortgageMember
Commercial real estate: other construction and land development
Summary of loans, by loan type
Total loans	1,522,571us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_CommercialRealEstateOtherConstructionAndLandDevelopmentReceivableMember	1,414,977us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_CommercialRealEstateOtherConstructionAndLandDevelopmentReceivableMember
Consumer Loan
Summary of loans, by loan type
Total loans	59,254us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember	61,137us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = us-gaap_ConsumerLoanMember
Foreign
Summary of loans, by loan type
Total loans	$ 185,457us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_ForeignReceivablesMember	$ 185,221us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = iboc_ForeignReceivablesMember

X

- Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=iboc_CommercialRealEstateOtherConstructionAndLandDevelopmentReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=iboc_ForeignReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=iboc_LoansReceivableCommercialFinancialAndAgriculturalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_ConsumerLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: