Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-23-000072-index-headers.html | 2023-04-11 16:47:40 | |
| 0000860413-23-000072-index.html | 2023-04-11 16:47:40 | |
| 0000860413-23-000072.txt | 2023-04-11 16:47:40 | |
 0000860413-23-000072-xbrl.zip | 8231238 | 2023-04-11 16:47:40 |
| fibk-20230411.htm | 2257265 | 2023-04-11 16:47:40 |
| fibk-20230411.xsd | 4521 | 2023-04-11 16:47:40 |
| fibk-20230411_def.xml | 6297 | 2023-04-11 16:47:40 |
 fibk-20230411_g1.jpg | 48081 | 2023-04-11 16:47:40 |
 fibk-20230411_g10.jpg | 1019660 | 2023-04-11 16:47:40 |
 fibk-20230411_g11.jpg | 1246358 | 2023-04-11 16:47:40 |
 fibk-20230411_g12.jpg | 117705 | 2023-04-11 16:47:40 |
 fibk-20230411_g13.jpg | 412117 | 2023-04-11 16:47:40 |
 fibk-20230411_g14.jpg | 319017 | 2023-04-11 16:47:40 |
 fibk-20230411_g15.jpg | 104594 | 2023-04-11 16:47:40 |
 fibk-20230411_g16.jpg | 88087 | 2023-04-11 16:47:40 |
 fibk-20230411_g17.jpg | 88307 | 2023-04-11 16:47:40 |
 fibk-20230411_g18.jpg | 158148 | 2023-04-11 16:47:40 |
 fibk-20230411_g19.jpg | 97821 | 2023-04-11 16:47:40 |
 fibk-20230411_g2.jpg | 332173 | 2023-04-11 16:47:40 |
 fibk-20230411_g20.jpg | 202114 | 2023-04-11 16:47:40 |
 fibk-20230411_g21.jpg | 166702 | 2023-04-11 16:47:40 |
 fibk-20230411_g22.jpg | 160462 | 2023-04-11 16:47:40 |
 fibk-20230411_g23.jpg | 87806 | 2023-04-11 16:47:40 |
 fibk-20230411_g24.jpg | 104901 | 2023-04-11 16:47:40 |
 fibk-20230411_g25.jpg | 157755 | 2023-04-11 16:47:40 |
 fibk-20230411_g26.jpg | 199151 | 2023-04-11 16:47:40 |
 fibk-20230411_g27.jpg | 159232 | 2023-04-11 16:47:40 |
 fibk-20230411_g28.jpg | 88939 | 2023-04-11 16:47:40 |
 fibk-20230411_g29.jpg | 109559 | 2023-04-11 16:47:40 |
 fibk-20230411_g3.jpg | 508741 | 2023-04-11 16:47:40 |
 fibk-20230411_g30.jpg | 80265 | 2023-04-11 16:47:40 |
 fibk-20230411_g31.jpg | 90691 | 2023-04-11 16:47:40 |
 fibk-20230411_g32.jpg | 172267 | 2023-04-11 16:47:40 |
 fibk-20230411_g33.jpg | 83094 | 2023-04-11 16:47:40 |
 fibk-20230411_g34.jpg | 87676 | 2023-04-11 16:47:40 |
 fibk-20230411_g35.jpg | 40047 | 2023-04-11 16:47:40 |
 fibk-20230411_g36.jpg | 79877 | 2023-04-11 16:47:40 |
 fibk-20230411_g37.jpg | 143411 | 2023-04-11 16:47:40 |
 fibk-20230411_g38.jpg | 93585 | 2023-04-11 16:47:40 |
 fibk-20230411_g39.jpg | 185805 | 2023-04-11 16:47:40 |
 fibk-20230411_g4.jpg | 7749 | 2023-04-11 16:47:40 |
 fibk-20230411_g40.jpg | 46653 | 2023-04-11 16:47:40 |
 fibk-20230411_g41.jpg | 42267 | 2023-04-11 16:47:40 |
 fibk-20230411_g42.jpg | 46606 | 2023-04-11 16:47:40 |
 fibk-20230411_g43.jpg | 174172 | 2023-04-11 16:47:40 |
 fibk-20230411_g44.jpg | 343661 | 2023-04-11 16:47:40 |
 fibk-20230411_g45.jpg | 31239 | 2023-04-11 16:47:40 |
 fibk-20230411_g46.jpg | 40720 | 2023-04-11 16:47:40 |
 fibk-20230411_g47.jpg | 90316 | 2023-04-11 16:47:40 |
 fibk-20230411_g48.jpg | 80403 | 2023-04-11 16:47:40 |
 fibk-20230411_g49.jpg | 84053 | 2023-04-11 16:47:40 |
 fibk-20230411_g5.jpg | 143477 | 2023-04-11 16:47:40 |
 fibk-20230411_g50.jpg | 257823 | 2023-04-11 16:47:40 |
 fibk-20230411_g51.jpg | 16240 | 2023-04-11 16:47:40 |
 fibk-20230411_g52.jpg | 1327477 | 2023-04-11 16:47:40 |
 fibk-20230411_g53.jpg | 591265 | 2023-04-11 16:47:40 |
 fibk-20230411_g6.jpg | 90794 | 2023-04-11 16:47:40 |
 fibk-20230411_g7.jpg | 80687 | 2023-04-11 16:47:40 |
 fibk-20230411_g8.jpg | 95044 | 2023-04-11 16:47:40 |
 fibk-20230411_g9.jpg | 186348 | 2023-04-11 16:47:40 |
| fibk-20230411_htm.xml | 206915 | 2023-04-11 16:47:40 |
| fibk-20230411_lab.xml | 9970 | 2023-04-11 16:47:40 |
| fibk-20230411_pre.xml | 5264 | 2023-04-11 16:47:40 |
| FilingSummary.xml | 4378 | 2023-04-11 16:47:40 |
| Financial_Report.xlsx | 10231 | 2023-04-11 16:47:40 |
| MetaLinks.json | 149905 | 2023-04-11 16:47:40 |
| R1.htm | 10856 | 2023-04-11 16:47:40 |
| R2.htm | 219447 | 2023-04-11 16:47:40 |
| report.css | 2767 | 2023-04-11 16:47:40 |
| Show.js | 1085 | 2023-04-11 16:47:40 |