XML 55 R39.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Deposits (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2023
Deposits. |
Schedule of deposits and related interest expense | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | 2023 | ​ | 2022 |
​ | ​ | (Dollars in Thousands) |
Deposits: |  | ​ |  |  | ​ |  | ​
Demand - non-interest bearing | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic | ​ | $ | 4,126,635 | ​ | $ | 4,744,299 | ​
Foreign | ​ |  | 904,210 | ​ |  | 1,101,756 | ​
Total demand non-interest bearing | ​ |  | 5,030,845 | ​ |  | 5,846,055 | ​
Savings and interest bearing demand | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic | ​ |  | 3,161,411 | ​ |  | 3,448,717 | ​
Foreign | ​ |  | 1,207,121 | ​ |  | 1,297,051 | ​
Total savings and interest bearing demand | ​ |  | 4,368,532 | ​ |  | 4,745,768 | ​
Time, certificates of deposit $100,000 or more | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic | ​ |  | 763,419 | ​ |  | 652,073 | ​
Foreign | ​ |  | 1,103,710 | ​ |  | 892,619 | ​
Less than $100,000 | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic | ​ |  | 289,565 | ​ |  | 276,660 | ​
Foreign | ​ |  | 268,483 | ​ |  | 246,832 | ​
Total time, certificates of deposit | ​ |  | 2,425,177 | ​ |  | 2,068,184 | ​
Total deposits | ​ | $ | 11,824,554 | ​ | $ | 12,660,007 | ​
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | 2023 | ​ | 2022 | ​ | 2021 |
​ | ​ | (Dollars in Thousands) |
Interest expense: |  | ​ |  |  | ​ |  |  | ​ |  | ​
Savings and interest bearing demand | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic |  | $ | 42,148 | ​ | $ | 9,196 | ​ | $ | 3,268 | ​
Foreign |  | ​ | 18,189 | ​ |  | 3,490 | ​ |  | 842 | ​
Total savings and interest bearing demand |  | ​ | 60,337 | ​ |  | 12,686 | ​ |  | 4,110 | ​
Time, certificates of deposit $100,000 or more | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic |  | ​ | 18,597 | ​ |  | 5,528 | ​ |  | 6,652 | ​
Foreign |  | ​ | 25,471 | ​ |  | 3,867 | ​ |  | 3,452 | ​
Less than $100,000 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Domestic |  | ​ | 4,592 | ​ |  | 1,027 | ​ |  | 984 | ​
Foreign |  | ​ | 4,498 | ​ |  | 735 | ​ |  | 567 | ​
Total time, certificates of deposit |  | ​ | 53,158 | ​ |  | 11,157 | ​ |  | 11,655 | ​
Total interest expense on deposits | ​ | $ | 113,495 | ​ | $ | 23,843 | ​ | $ | 15,765 | ​
​
Scheduled maturities of time deposits | Scheduled maturities of time deposits as of December 31, 2023 were as follows: ​
​ | ​ | ​ | ​ | ​
​ |  | Total |
​ | ​ | (in thousands) |
2024 | ​ | $ | 2,301,914 | ​
2025 | ​ |  | 85,385 | ​
2026 | ​ |  | 23,102 | ​
2027 | ​ |  | 14,200 | ​
2028 | ​ |  | 573 | ​
Thereafter | ​ |  | 3 | ​
Total | ​ | $ | 2,425,177 | ​
Scheduled maturities of time deposits in amounts of $100,000 or more | ​
​ | ​ | ​ | ​
​ | ​ | Total
​ | ​ | (in thousands)
Due within 3 months or less |  | $ | 859,734
Due after 3 months and within 6 months | ​ |  | 517,994
Due after 6 months and within 12 months | ​ |  | 409,193
Due after 12 months | ​ |  | 80,208
​ | ​ | $ | 1,867,129

X
- References No definition available. + Details
Name: | iboc_DepositsDisclosureAbstract
Namespace Prefix: | iboc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of information pertaining to deposits and related interest expense. + References No definition available. + Details
Name: | iboc_ScheduleOfDepositsAndRelatedInterestExpenseTableTextBlock
Namespace Prefix: | iboc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of time deposits, classified with respect to their maturities. + References No definition available. + Details
Name: | iboc_ScheduleOfTimeDepositsContractualMaturitiesTableTextBlock
Namespace Prefix: | iboc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of time deposits with balances of 100,000 dollars or more, along with contractual maturities. + References No definition available. + Details
Name: | iboc_ScheduleOfTimeDepositsWithBalancesOf100000OrMoreWithContractualMaturitiesTableTextBlock
Namespace Prefix: | iboc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration