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| 0000860413-18-000069-index.html | 2018-05-08 17:33:50 | |
| 0000860413-18-000069.txt | 2018-05-08 17:33:50 | |
 0000860413-18-000069-xbrl.zip | 385186 | 2018-05-08 17:33:50 |
| fibk-20180331.xml | 4632945 | 2018-05-08 17:33:50 |
| fibk-20180331.xsd | 74992 | 2018-05-08 17:33:50 |
| fibk-20180331x10q.htm | 2570236 | 2018-05-08 17:33:50 |
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| fibk-20180331xex32.htm | 4739 | 2018-05-08 17:33:50 |
| fibk-20180331_cal.xml | 188687 | 2018-05-08 17:33:50 |
| fibk-20180331_def.xml | 461752 | 2018-05-08 17:33:50 |
| fibk-20180331_lab.xml | 1094876 | 2018-05-08 17:33:50 |
| fibk-20180331_pre.xml | 666965 | 2018-05-08 17:33:50 |
| FilingSummary.xml | 45476 | 2018-05-08 17:33:50 |
| Financial_Report.xlsx | 121003 | 2018-05-08 17:33:50 |
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| report.css | 2767 | 2018-05-08 17:33:50 |
| Show.js | 1410 | 2018-05-08 17:33:50 |