XML 47 R36.htm IDEA: XBRL DOCUMENT v3.21.1

Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 9,105	$ 8,238
Past due	33,372	38,258
Loans, current	7,428,986	7,503,496
Total loans	7,462,358	7,541,754
30 to 59 Days
Financing receivable recorded investment
Past due	16,426	9,307
60 to 89 Days
Financing receivable recorded investment
Past due	7,137	3,606
90 Days or Greater
Financing receivable recorded investment
Past due	9,809	25,345
Commercial, financial and agricultural
Financing receivable recorded investment
Total loans	4,680,883	4,516,288
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	492	318
Past due	5,367	3,603
Loans, current	1,735,239	1,782,333
Total loans	1,740,606	1,785,936
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	4,060	1,931
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	344	1,109
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	963	563
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	72	186
Past due	6,930	2,840
Loans, current	2,414,362	2,286,468
Total loans	2,421,292	2,289,308
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	3,004	2,435
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	3,854	219
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	72	186
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Financing receivable recorded investment
Past due		126
Loans, current	518,985	440,918
Total loans	518,985	441,044
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due		126
Real estate - construction
Financing receivable recorded investment
Total loans	1,653,418	1,846,757
Real estate - construction | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1
Past due	1,652	18,500
Loans, current	1,651,766	1,828,257
Total loans	1,653,418	1,846,757
Real estate - construction | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Past due	1,651	1,059
Real estate - construction | Domestic | Commercial Real Estate: other construction and land development | 60 to 89 Days
Financing receivable recorded investment
Past due		854
Real estate - construction | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Past due	1	16,587
Real estate - mortgage
Financing receivable recorded investment
Total loans	950,782	999,144
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	7,061	5,890
Past due	11,425	9,490
Loans, current	390,272	395,629
Total loans	401,697	405,119
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	3,530	2,399
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	638	926
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	7,257	6,165
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	915	1,197
Past due	3,226	2,005
Loans, current	545,859	592,020
Total loans	549,085	594,025
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Past due	925	561
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Past due	1,349	247
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Past due	952	1,197
Consumer
Financing receivable recorded investment
Total loans	39,743	40,595
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	31	79
Past due	334	468
Loans, current	39,409	40,127
Total loans	39,743	40,595
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Past due	289	318
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Past due	14	71
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Past due	31	79
Foreign
Financing receivable recorded investment
Total loans	137,532	138,970
Foreign | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	533	568
Past due	4,438	1,226
Loans, current	133,094	137,744
Total loans	137,532	138,970
Foreign | Foreign | 30 to 59 Days
Financing receivable recorded investment
Past due	2,967	478
Foreign | Foreign | 60 to 89 Days
Financing receivable recorded investment
Past due	938	180
Foreign | Foreign | 90 Days or Greater
Financing receivable recorded investment
Past due	$ 533	$ 568

X

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of financing receivable not past due.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953401-111524

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

+ Details

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

X

- Definition

Amount of financing receivable past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953401-111524

+ Details

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

X

- Definition

Amount, before allowance for credit loss, of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919230-210447

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

+ Details

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

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=iboc_CommercialFinancialAndAgriculturalRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_GeographicDistributionAxis=us-gaap_GeographicDistributionDomesticMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=iboc_CommercialRealEstateFarmlandAndCommercialReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=iboc_CommercialRealEstateMultifamilyReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LienCategoryAxis=us-gaap_SeniorLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LienCategoryAxis=us-gaap_JuniorLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=iboc_ForeignPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_GeographicDistributionAxis=us-gaap_GeographicDistributionForeignMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: