XML 58 R42.htm IDEA: XBRL DOCUMENT
v3.20.4

Other Borrowed Funds (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Schedule of other borrowed funds | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, |
​ | ​ | 2020 | ​ | 2019 |
​ | ​ | (Dollars in Thousands) |
Federal Home Loan Bank advances—short-term |  | ​ |  |  | ​ |  | ​
Balance at year end | ​ | $ | — | ​ | $ | 190,000 | ​
Rate on balance outstanding at year end | ​ |  | — | % |  | 1.48 | %
Average daily balance | ​ | $ | 110,776 | ​ | $ | 190,431 | ​
Average rate | ​ |  | 1.19 | % |  | 2.60 | %
Maximum amount outstanding at any month end | ​ | $ | 292,000 | ​ | $ | 371,775 | ​
Federal Home Loan Bank advances—long-term(1) | ​ | ​ | ​ | ​ | ​ | ​ | ​
Balance at year end | ​ | $ | 436,327 | ​ | $ | 436,511 | ​
Rate on balance outstanding at year end | ​ |  | 1.73 | % |  | 1.73 | %
Average daily balance | ​ | $ | 436,411 | ​ | $ | 436,593 | ​
Average rate | ​ |  | 1.71 | % |  | 1.71 | %
Maximum amount outstanding at any month end | ​ | $ | 436,495 | ​ | $ | 436,675 | ​
​
| (1) | Long-term advances at December 31, 2020 and December 31, 2019 consisted of both amortizing and non-amortizing advances. The non-amortizing advances mature in the following increments: $75,000,000 in July 2028, $100,000,000 in March 2033 and $250,000,000 in August 2033 and are callable by the FHLB on a quarterly basis. Two amortizing advances are outstanding at December 31, 2020 in the amounts of $3,091,000 and $8,236,000 and mature in December 2033 and November 2033, respectively. The amortization on the amortizing long-term advances totals approximately $189,000, $194,000, $199,000, $204,000 and $210,000 for the years ending December 31, 2021, December 31,
|  | 2022, December 31, 2023, December 31, 2024 and December 31, 2025, respectively.

X
- Definition Tabular disclosure of all borrowed funds not defined anywhere else in the taxonomy. Includes Federal Home Loan Bank borrowings, which are short and long-term fixed borrowings. + References No definition available. + Details
Name: | iboc_ScheduleOfOtherBorrowedFundsTableTextBlock
Namespace Prefix: | iboc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration