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| 0000860413-18-000171-index.html | 2018-11-07 14:29:41 | |
| 0000860413-18-000171.txt | 2018-11-07 14:29:41 | |
 0000860413-18-000171-xbrl.zip | 463213 | 2018-11-07 14:29:41 |
| fibk-20180930.xml | 5594374 | 2018-11-07 14:29:41 |
| fibk-20180930.xsd | 82645 | 2018-11-07 14:29:41 |
| fibk-20180930x10q.htm | 3254641 | 2018-11-07 14:29:41 |
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| fibk-20180930_cal.xml | 195696 | 2018-11-07 14:29:41 |
| fibk-20180930_def.xml | 538041 | 2018-11-07 14:29:41 |
| fibk-20180930_lab.xml | 1194884 | 2018-11-07 14:29:41 |
| fibk-20180930_pre.xml | 730565 | 2018-11-07 14:29:41 |
| FilingSummary.xml | 45540 | 2018-11-07 14:29:41 |
| Financial_Report.xlsx | 135732 | 2018-11-07 14:29:41 |
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| report.css | 2767 | 2018-11-07 14:29:41 |
| Show.js | 1085 | 2018-11-07 14:29:41 |