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| 0000860413-17-000027-index.html | 2017-08-09 15:58:34 | |
| 0000860413-17-000027.txt | 2017-08-09 15:58:34 | |
 0000860413-17-000027-xbrl.zip | 437453 | 2017-08-09 15:58:34 |
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| fibk-20170630.xml | 5356899 | 2017-08-09 15:58:34 |
| fibk-20170630.xsd | 74761 | 2017-08-09 15:58:34 |
| fibk-20170630x10q.htm | 3029946 | 2017-08-09 15:58:34 |
| fibk-20170630xex31.htm | 74646 | 2017-08-09 15:58:34 |
| fibk-20170630xex311.htm | 12207 | 2017-08-09 15:58:34 |
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| fibk-20170630xex32.htm | 4705 | 2017-08-09 15:58:34 |
| fibk-20170630_cal.xml | 154974 | 2017-08-09 15:58:34 |
| fibk-20170630_def.xml | 557506 | 2017-08-09 15:58:34 |
| fibk-20170630_lab.xml | 1138509 | 2017-08-09 15:58:34 |
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| fibk20170630xex3-2.htm | 139009 | 2017-08-09 15:58:34 |
| FilingSummary.xml | 38224 | 2017-08-09 15:58:34 |
| Financial_Report.xlsx | 126537 | 2017-08-09 15:58:34 |
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| report.css | 2767 | 2017-08-09 15:58:34 |
| Show.js | 1410 | 2017-08-09 15:58:34 |