Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-25-000070-index-headers.html | 2025-05-23 16:35:06 | |
| 0000860413-25-000070-index.html | 2025-05-23 16:35:06 | |
| 0000860413-25-000070.txt | 2025-05-23 16:35:06 | |
 0000860413-25-000070-xbrl.zip | 98114 | 2025-05-23 16:35:06 |
| fibk-20250520.htm | 53964 | 2025-05-23 16:35:06 |
| fibk-20250520.xsd | 1773 | 2025-05-23 16:35:06 |
| fibk-20250520_htm.xml | 2823 | 2025-05-23 16:35:06 |
| fibk-20250520_lab.xml | 22788 | 2025-05-23 16:35:06 |
| fibk-20250520_pre.xml | 13037 | 2025-05-23 16:35:06 |
| fibk-20250523xex_31bylaws.htm | 295324 | 2025-05-23 16:35:06 |
| fibk-20250523xex_32bylaws.htm | 299538 | 2025-05-23 16:35:06 |
| FilingSummary.xml | 1618 | 2025-05-23 16:35:06 |
 image_0.jpg | 16240 | 2025-05-23 16:35:06 |
 image_0a.jpg | 16240 | 2025-05-23 16:35:06 |
| MetaLinks.json | 17373 | 2025-05-23 16:35:06 |
| R1.htm | 39592 | 2025-05-23 16:35:06 |
| report.css | 2767 | 2025-05-23 16:35:06 |
| Show.js | 1085 | 2025-05-23 16:35:06 |