XML 98 R63.htm IDEA: XBRL DOCUMENT v2.4.0.6

Allowance for Probable Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for probable loan losses
Balance at the beginning of the period	$ 84,482	$ 95,393	$ 73,461
Losses charged to allowance	(22,899)	(35,240)	(38,539)
Recoveries credited to allowance	5,291	1,517	1,638
Net losses charged to allowance	(17,608)	(33,723)	(36,901)
Provision (credit) charged to operations	17,318	22,812	58,833
Balance at the end of the period	84,192	84,482	95,393
Commercial
Allowance for probable loan losses
Balance at the beginning of the period	22,046
Losses charged to allowance	(16,130)
Recoveries credited to allowance	4,126
Net losses charged to allowance	(12,004)
Provision (credit) charged to operations	16,575
Balance at the end of the period	26,617
Commercial real estate: other construction and land development
Allowance for probable loan losses
Balance at the beginning of the period	26,695
Losses charged to allowance	(1,467)
Recoveries credited to allowance	171
Net losses charged to allowance	(1,296)
Provision (credit) charged to operations	(5,459)
Balance at the end of the period	19,940
Risks related to family development loans
Minimum number of family development loans	1
Maximum number of family development loans	4
Commercial real estate: farmland and commercial
Allowance for probable loan losses
Balance at the beginning of the period	16,340
Losses charged to allowance	(1,955)
Recoveries credited to allowance	296
Net losses charged to allowance	(1,659)
Provision (credit) charged to operations	9,546
Balance at the end of the period	24,227
Commercial real estate: multifamily
Allowance for probable loan losses
Balance at the beginning of the period	53
Provision (credit) charged to operations	950
Balance at the end of the period	1,003
Residential: first lien
Allowance for probable loan losses
Balance at the beginning of the period	10,059
Losses charged to allowance	(805)
Recoveries credited to allowance	28
Net losses charged to allowance	(777)
Provision (credit) charged to operations	(4,720)
Balance at the end of the period	4,562
Residential: junior lien
Allowance for probable loan losses
Balance at the beginning of the period	2,611
Losses charged to allowance	(1,304)
Recoveries credited to allowance	300
Net losses charged to allowance	(1,004)
Provision (credit) charged to operations	3,153
Balance at the end of the period	4,760
Consumer
Allowance for probable loan losses
Balance at the beginning of the period	6,241
Losses charged to allowance	(1,067)
Recoveries credited to allowance	211
Net losses charged to allowance	(856)
Provision (credit) charged to operations	(3,661)
Balance at the end of the period	1,724
Foreign
Allowance for probable loan losses
Balance at the beginning of the period	437
Losses charged to allowance	(171)
Recoveries credited to allowance	159
Net losses charged to allowance	(12)
Provision (credit) charged to operations	934
Balance at the end of the period	$ 1,359

X

- Definition

Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, net of collections of loans and lease receivables which had previously been fully or partially charged off as bad debts.

+ References

No definition available.

+ Details

Name:	iboc_AllowanceForLoanAndLeaseLossesWriteOffsNet
Namespace Prefix:	iboc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Reflects an add back to the net allowance balance for loans and lease receivables for recoveries on previously charged off loan receivables.

+ References

No definition available.

+ Details

Name:	iboc_AllowanceForLoansAndLeasesLossesRecoveriesOfBadDebts
Namespace Prefix:	iboc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Reflects the maximum number of family development loans that include restrictive underwriting standards that inhibit the buys from obtaining long term financing and excessive housing and lot inventory in the market.

+ References

No definition available.

+ Details

Name:	iboc_MaximumNumberOfFamilyDevelopmentLoans
Namespace Prefix:	iboc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Reflects the minimum number of family development loans that include restrictive underwriting standards that inhibit the buys from obtaining long term financing and excessive housing and lot inventory in the market.

+ References

No definition available.

+ Details

Name:	iboc_MinimumNumberOfFamilyDevelopmentLoans
Namespace Prefix:	iboc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	iboc_RisksRelatedToFamilyDevelopmentLoansAbstract
Namespace Prefix:	iboc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Reflects the gross amount charged against earnings during the period as credit losses (bad debt expense) based on review of the loan and lease portfolio and application of the methodology for estimating credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-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 SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 7

-Subparagraph d



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesProvisionForLossGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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

X

- Definition

Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, typically because they are considered to be not salvageable or have been purchased by unconsolidated collection entities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-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 SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 7

-Subparagraph d



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The allowance for loan and lease losses represents the reserve to cover probable credit losses related to specifically identified loans and leases, as well as probable credit losses inherent in the remainder of the loan portfolio as of the balance sheet date. For banks, include currently required allocated transfer risk reserves. Include carryover of or adjustments to the allowance for loan losses in connection with business combinations determined to be appropriate.

+ References

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

-Publisher OTS

-Name Federal Regulation (FR)

-Number Title 12

-Chapter V

-Section 563c.102

-Paragraph 8

-Subparagraph a(ii)

-Subsection I

-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.



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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-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 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 7

-Subparagraph d



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 8, 9

-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 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant