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| 0000860413-17-000052-index.html | 2017-11-08 12:56:40 | |
| 0000860413-17-000052.txt | 2017-11-08 12:56:40 | |
 0000860413-17-000052-xbrl.zip | 420708 | 2017-11-08 12:56:40 |
| fibk-20170930.xml | 5490469 | 2017-11-08 12:56:40 |
| fibk-20170930.xsd | 79605 | 2017-11-08 12:56:40 |
| fibk-20170930x10q.htm | 3139667 | 2017-11-08 12:56:40 |
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| fibk-20170930xex32.htm | 4696 | 2017-11-08 12:56:40 |
| fibk-20170930_cal.xml | 209643 | 2017-11-08 12:56:40 |
| fibk-20170930_def.xml | 408137 | 2017-11-08 12:56:40 |
| fibk-20170930_lab.xml | 1139367 | 2017-11-08 12:56:40 |
| fibk-20170930_pre.xml | 651642 | 2017-11-08 12:56:40 |
| FilingSummary.xml | 44390 | 2017-11-08 12:56:40 |
| Financial_Report.xlsx | 131302 | 2017-11-08 12:56:40 |
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| report.css | 2767 | 2017-11-08 12:56:40 |
| Show.js | 1410 | 2017-11-08 12:56:40 |