Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-25-000077-index-headers.html | 2025-06-02 09:26:59 | |
| 0000860413-25-000077-index.html | 2025-06-02 09:26:59 | |
| 0000860413-25-000077.txt | 2025-06-02 09:26:59 | |
 0000860413-25-000077-xbrl.zip | 30897 | 2025-06-02 09:26:59 |
| fibk-20250601.htm | 36710 | 2025-06-02 09:26:59 |
| fibk-20250601.xsd | 1773 | 2025-06-02 09:26:59 |
| fibk-20250601_htm.xml | 2723 | 2025-06-02 09:26:59 |
| fibk-20250601_lab.xml | 22788 | 2025-06-02 09:26:59 |
| fibk-20250601_pre.xml | 13037 | 2025-06-02 09:26:59 |
| fibk-20250602xex_101employ.htm | 114195 | 2025-06-02 09:26:59 |
| fibk-20250602xex_991pressr.htm | 8981 | 2025-06-02 09:26:59 |
 fibslogo2linea04a.jpg | 165531 | 2025-06-02 09:26:59 |
| FilingSummary.xml | 1618 | 2025-06-02 09:26:59 |
| MetaLinks.json | 17373 | 2025-06-02 09:26:59 |
| R1.htm | 38077 | 2025-06-02 09:26:59 |
| report.css | 2767 | 2025-06-02 09:26:59 |
| Show.js | 1085 | 2025-06-02 09:26:59 |