Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-23-000115-index-headers.html | 2023-05-25 13:44:06 | |
| 0000860413-23-000115-index.html | 2023-05-25 13:44:06 | |
| 0000860413-23-000115.txt | 2023-05-25 13:44:06 | |
 0000860413-23-000115-xbrl.zip | 54555 | 2023-05-25 13:44:06 |
| fibk-20230524.htm | 103309 | 2023-05-25 13:44:06 |
| fibk-20230524.xsd | 1890 | 2023-05-25 13:44:06 |
| fibk-20230524_htm.xml | 11483 | 2023-05-25 13:44:06 |
| fibk-20230524_lab.xml | 25138 | 2023-05-25 13:44:06 |
| fibk-20230524_pre.xml | 13035 | 2023-05-25 13:44:06 |
| fibk-20230525xex102.htm | 74141 | 2023-05-25 13:44:06 |
| fibk-20230525xex103.htm | 100150 | 2023-05-25 13:44:06 |
| fibk-20230525xex21.htm | 46931 | 2023-05-25 13:44:06 |
| fibk-20230525xex31.htm | 35335 | 2023-05-25 13:44:06 |
| FilingSummary.xml | 1763 | 2023-05-25 13:44:06 |
| Financial_Report.xlsx | 5720 | 2023-05-25 13:44:06 |
| MetaLinks.json | 17472 | 2023-05-25 13:44:06 |
| R1.htm | 39607 | 2023-05-25 13:44:06 |
| report.css | 2767 | 2023-05-25 13:44:06 |
| Show.js | 1085 | 2023-05-25 13:44:06 |