Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-24-000053-index-headers.html | 2024-04-11 16:24:07 | |
| 0000860413-24-000053-index.html | 2024-04-11 16:24:07 | |
| 0000860413-24-000053.txt | 2024-04-11 16:24:07 | |
 0000860413-24-000053-xbrl.zip | 6432289 | 2024-04-11 16:24:07 |
| fibk-20240411.htm | 4288834 | 2024-04-11 16:24:07 |
| fibk-20240411.xsd | 4511 | 2024-04-11 16:24:07 |
| fibk-20240411_def.xml | 6291 | 2024-04-11 16:24:07 |
 fibk-20240411_g1.jpg | 48081 | 2024-04-11 16:24:07 |
 fibk-20240411_g10.gif | 253233 | 2024-04-11 16:24:07 |
 fibk-20240411_g11.jpg | 344242 | 2024-04-11 16:24:07 |
 fibk-20240411_g12.jpg | 482833 | 2024-04-11 16:24:07 |
 fibk-20240411_g13.jpg | 59383 | 2024-04-11 16:24:07 |
 fibk-20240411_g14.jpg | 156014 | 2024-04-11 16:24:07 |
 fibk-20240411_g15.jpg | 41947 | 2024-04-11 16:24:07 |
 fibk-20240411_g16.jpg | 43034 | 2024-04-11 16:24:07 |
 fibk-20240411_g17.jpg | 41140 | 2024-04-11 16:24:07 |
 fibk-20240411_g18.jpg | 43893 | 2024-04-11 16:24:07 |
 fibk-20240411_g19.jpg | 47642 | 2024-04-11 16:24:07 |
 fibk-20240411_g2.jpg | 2013029 | 2024-04-11 16:24:07 |
 fibk-20240411_g20.jpg | 43462 | 2024-04-11 16:24:07 |
 fibk-20240411_g21.jpg | 42270 | 2024-04-11 16:24:07 |
 fibk-20240411_g22.jpg | 42569 | 2024-04-11 16:24:07 |
 fibk-20240411_g23.jpg | 45840 | 2024-04-11 16:24:07 |
 fibk-20240411_g24.jpg | 46420 | 2024-04-11 16:24:07 |
 fibk-20240411_g25.jpg | 44297 | 2024-04-11 16:24:07 |
 fibk-20240411_g26.jpg | 43510 | 2024-04-11 16:24:07 |
 fibk-20240411_g27.jpg | 42132 | 2024-04-11 16:24:07 |
 fibk-20240411_g28.jpg | 43126 | 2024-04-11 16:24:07 |
 fibk-20240411_g29.jpg | 77511 | 2024-04-11 16:24:07 |
 fibk-20240411_g3.jpg | 449869 | 2024-04-11 16:24:07 |
 fibk-20240411_g30.jpg | 66473 | 2024-04-11 16:24:07 |
 fibk-20240411_g31.jpg | 68954 | 2024-04-11 16:24:07 |
 fibk-20240411_g32.jpg | 50257 | 2024-04-11 16:24:07 |
 fibk-20240411_g33.jpg | 43656 | 2024-04-11 16:24:07 |
 fibk-20240411_g34.jpg | 41909 | 2024-04-11 16:24:07 |
 fibk-20240411_g35.jpg | 43361 | 2024-04-11 16:24:07 |
 fibk-20240411_g36.jpg | 44546 | 2024-04-11 16:24:07 |
 fibk-20240411_g37.jpg | 41504 | 2024-04-11 16:24:07 |
 fibk-20240411_g38.gif | 35245 | 2024-04-11 16:24:07 |
 fibk-20240411_g39.gif | 31818 | 2024-04-11 16:24:07 |
 fibk-20240411_g4.jpg | 7749 | 2024-04-11 16:24:07 |
 fibk-20240411_g40.gif | 34528 | 2024-04-11 16:24:07 |
 fibk-20240411_g41.gif | 205964 | 2024-04-11 16:24:07 |
 fibk-20240411_g42.jpg | 343661 | 2024-04-11 16:24:07 |
 fibk-20240411_g43.gif | 21116 | 2024-04-11 16:24:07 |
 fibk-20240411_g44.gif | 27687 | 2024-04-11 16:24:07 |
 fibk-20240411_g45.gif | 64300 | 2024-04-11 16:24:07 |
 fibk-20240411_g46.gif | 59407 | 2024-04-11 16:24:07 |
 fibk-20240411_g47.gif | 62501 | 2024-04-11 16:24:07 |
 fibk-20240411_g48.jpg | 257823 | 2024-04-11 16:24:07 |
 fibk-20240411_g49.jpg | 299716 | 2024-04-11 16:24:07 |
 fibk-20240411_g5.jpg | 232649 | 2024-04-11 16:24:07 |
 fibk-20240411_g50.jpg | 157092 | 2024-04-11 16:24:07 |
 fibk-20240411_g6.jpg | 338940 | 2024-04-11 16:24:07 |
 fibk-20240411_g7.gif | 69821 | 2024-04-11 16:24:07 |
 fibk-20240411_g8.gif | 60688 | 2024-04-11 16:24:07 |
 fibk-20240411_g9.gif | 140551 | 2024-04-11 16:24:07 |
| fibk-20240411_htm.xml | 150024 | 2024-04-11 16:24:07 |
| fibk-20240411_lab.xml | 9629 | 2024-04-11 16:24:07 |
| fibk-20240411_pre.xml | 5258 | 2024-04-11 16:24:07 |
| FilingSummary.xml | 4291 | 2024-04-11 16:24:07 |
| MetaLinks.json | 184810 | 2024-04-11 16:24:07 |
| R1.htm | 10859 | 2024-04-11 16:24:07 |
| R2.htm | 194872 | 2024-04-11 16:24:07 |
| report.css | 2767 | 2024-04-11 16:24:07 |
| Show.js | 1085 | 2024-04-11 16:24:07 |