Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-23-000014-index-headers.html | 2023-01-26 16:13:45 | |
| 0000860413-23-000014-index.html | 2023-01-26 16:13:45 | |
| 0000860413-23-000014.txt | 2023-01-26 16:13:45 | |
 0000860413-23-000014-xbrl.zip | 71469 | 2023-01-26 16:13:45 |
| dec2022ip.htm | 36229 | 2023-01-26 16:13:45 |
 dec2022ip001.jpg | 292677 | 2023-01-26 16:13:45 |
 dec2022ip002.jpg | 304437 | 2023-01-26 16:13:45 |
 dec2022ip003.jpg | 98220 | 2023-01-26 16:13:45 |
 dec2022ip004.jpg | 137419 | 2023-01-26 16:13:45 |
 dec2022ip005.jpg | 103322 | 2023-01-26 16:13:45 |
 dec2022ip006.jpg | 86487 | 2023-01-26 16:13:45 |
 dec2022ip007.jpg | 74184 | 2023-01-26 16:13:45 |
 dec2022ip008.jpg | 108131 | 2023-01-26 16:13:45 |
 dec2022ip009.jpg | 96022 | 2023-01-26 16:13:45 |
 dec2022ip010.jpg | 88762 | 2023-01-26 16:13:45 |
 dec2022ip011.jpg | 112330 | 2023-01-26 16:13:45 |
 dec2022ip012.jpg | 66437 | 2023-01-26 16:13:45 |
 dec2022ip013.jpg | 59851 | 2023-01-26 16:13:45 |
 dec2022ip014.jpg | 79458 | 2023-01-26 16:13:45 |
 dec2022ip015.jpg | 113776 | 2023-01-26 16:13:45 |
 dec2022ip016.jpg | 128087 | 2023-01-26 16:13:45 |
 dec2022ip017.jpg | 273532 | 2023-01-26 16:13:45 |
 dec2022ip018.jpg | 114706 | 2023-01-26 16:13:45 |
 dec2022ip019.jpg | 107798 | 2023-01-26 16:13:45 |
 dec2022ip020.jpg | 88423 | 2023-01-26 16:13:45 |
 dec2022ip021.jpg | 86849 | 2023-01-26 16:13:45 |
| fibk-20221231x8kpr.htm | 1131647 | 2023-01-26 16:13:45 |
| fibk-20230126.htm | 41409 | 2023-01-26 16:13:45 |
| fibk-20230126.xsd | 1890 | 2023-01-26 16:13:45 |
| fibk-20230126_htm.xml | 10993 | 2023-01-26 16:13:45 |
| fibk-20230126_lab.xml | 24137 | 2023-01-26 16:13:45 |
| fibk-20230126_pre.xml | 12500 | 2023-01-26 16:13:45 |
 fibslogo2linea04.jpg | 165531 | 2023-01-26 16:13:45 |
| FilingSummary.xml | 1672 | 2023-01-26 16:13:45 |
| Financial_Report.xlsx | 5697 | 2023-01-26 16:13:45 |
| MetaLinks.json | 16948 | 2023-01-26 16:13:45 |
| R1.htm | 38100 | 2023-01-26 16:13:45 |
| report.css | 2767 | 2023-01-26 16:13:45 |
| Show.js | 1085 | 2023-01-26 16:13:45 |