Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-26-000097-index-headers.html | 2026-10-22 16:10:47 | |
| 0000860413-26-000097-index.html | 2026-10-22 16:10:47 | |
| 0000860413-26-000097.txt | 2026-10-22 16:10:47 | |
 0000860413-26-000097-xbrl.zip | 57175 | 2026-10-22 16:10:47 |
| fibk-20260930x8kpr.htm | 772869 | 2026-10-22 16:10:47 |
| fibk-20261022.htm | 32952 | 2026-10-22 16:10:47 |
| fibk-20261022.xsd | 2366 | 2026-10-22 16:10:47 |
| fibk-20261022_def.xml | 10969 | 2026-10-22 16:10:47 |
| fibk-20261022_htm.xml | 3208 | 2026-10-22 16:10:47 |
| fibk-20261022_lab.xml | 25241 | 2026-10-22 16:10:47 |
| fibk-20261022_pre.xml | 15324 | 2026-10-22 16:10:47 |
 fibslogo2linea04.jpg | 165531 | 2026-10-22 16:10:47 |
| FilingSummary.xml | 2091 | 2026-10-22 16:10:47 |
| MetaLinks.json | 20416 | 2026-10-22 16:10:47 |
| R1.htm | 13588 | 2026-10-22 16:10:47 |
| R2.htm | 27029 | 2026-10-22 16:10:47 |
| report.css | 2767 | 2026-10-22 16:10:47 |
| sep2026ip.htm | 40213 | 2026-10-22 16:10:47 |
 sep2026ip001.jpg | 127739 | 2026-10-22 16:10:47 |
 sep2026ip002.jpg | 339745 | 2026-10-22 16:10:47 |
 sep2026ip003.jpg | 107406 | 2026-10-22 16:10:47 |
 sep2026ip004.jpg | 100627 | 2026-10-22 16:10:47 |
 sep2026ip005.jpg | 172076 | 2026-10-22 16:10:47 |
 sep2026ip006.jpg | 74565 | 2026-10-22 16:10:47 |
 sep2026ip007.jpg | 220671 | 2026-10-22 16:10:47 |
 sep2026ip008.jpg | 101637 | 2026-10-22 16:10:47 |
 sep2026ip009.jpg | 80830 | 2026-10-22 16:10:47 |
 sep2026ip010.jpg | 79569 | 2026-10-22 16:10:47 |
 sep2026ip011.jpg | 113468 | 2026-10-22 16:10:47 |
 sep2026ip012.jpg | 130894 | 2026-10-22 16:10:47 |
 sep2026ip013.jpg | 82634 | 2026-10-22 16:10:47 |
 sep2026ip014.jpg | 95659 | 2026-10-22 16:10:47 |
 sep2026ip015.jpg | 99228 | 2026-10-22 16:10:47 |
 sep2026ip016.jpg | 75565 | 2026-10-22 16:10:47 |
 sep2026ip017.jpg | 86139 | 2026-10-22 16:10:47 |
 sep2026ip018.jpg | 103055 | 2026-10-22 16:10:47 |
 sep2026ip019.jpg | 260206 | 2026-10-22 16:10:47 |
 sep2026ip020.jpg | 113196 | 2026-10-22 16:10:47 |
 sep2026ip021.jpg | 111961 | 2026-10-22 16:10:47 |
| Show.js | 1085 | 2026-10-22 16:10:47 |