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|---|---|---|
 0000860413-23-000048-index-headers.html | 2023-03-10 17:14:06 | |
| 0000860413-23-000048-index.html | 2023-03-10 17:14:06 | |
| 0000860413-23-000048.txt | 2023-03-10 17:14:06 | |
 0000860413-23-000048-xbrl.zip | 8896117 | 2023-03-10 17:14:06 |
| fibk-20230310.htm | 2273795 | 2023-03-10 17:14:06 |
| fibk-20230310.xsd | 4521 | 2023-03-10 17:14:06 |
| fibk-20230310_def.xml | 6297 | 2023-03-10 17:14:06 |
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| fibk-20230310_htm.xml | 250704 | 2023-03-10 17:14:06 |
| fibk-20230310_lab.xml | 9970 | 2023-03-10 17:14:06 |
| fibk-20230310_pre.xml | 5264 | 2023-03-10 17:14:06 |
 fibklogoa.jpg | 16240 | 2023-03-10 17:14:06 |
| FilingSummary.xml | 4300 | 2023-03-10 17:14:06 |
| Financial_Report.xlsx | 9784 | 2023-03-10 17:14:06 |
| MetaLinks.json | 149905 | 2023-03-10 17:14:06 |
| R1.htm | 10856 | 2023-03-10 17:14:06 |
| R2.htm | 211748 | 2023-03-10 17:14:06 |
| report.css | 2767 | 2023-03-10 17:14:06 |
| Show.js | 1085 | 2023-03-10 17:14:06 |