Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-26-000025-index-headers.html | 2026-04-16 16:09:35 | |
| 0000860413-26-000025-index.html | 2026-04-16 16:09:35 | |
| 0000860413-26-000025.txt | 2026-04-16 16:09:35 | |
 0000860413-26-000025-xbrl.zip | 15664227 | 2026-04-16 16:09:35 |
| fibk-20260415.htm | 3495238 | 2026-04-16 16:09:35 |
| fibk-20260415.xsd | 4893 | 2026-04-16 16:09:35 |
| fibk-20260415_def.xml | 7546 | 2026-04-16 16:09:35 |
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 fibk-20260415_g38.gif | 23997 | 2026-04-16 16:09:35 |
 fibk-20260415_g39.gif | 30106 | 2026-04-16 16:09:35 |
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 fibk-20260415_g46.jpg | 188267 | 2026-04-16 16:09:35 |
 fibk-20260415_g5.gif | 68586 | 2026-04-16 16:09:35 |
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 fibk-20260415_g9.jpg | 1252920 | 2026-04-16 16:09:35 |
| fibk-20260415_htm.xml | 109655 | 2026-04-16 16:09:35 |
| fibk-20260415_lab.xml | 11327 | 2026-04-16 16:09:35 |
| fibk-20260415_pre.xml | 7270 | 2026-04-16 16:09:35 |
| FilingSummary.xml | 4133 | 2026-04-16 16:09:35 |
| MetaLinks.json | 211251 | 2026-04-16 16:09:35 |
| R1.htm | 10841 | 2026-04-16 16:09:35 |
| R2.htm | 160770 | 2026-04-16 16:09:35 |
| report.css | 2767 | 2026-04-16 16:09:35 |
| Show.js | 1085 | 2026-04-16 16:09:35 |