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| 0000860413-15-000013-index.html | 2015-05-07 16:38:05 | |
| 0000860413-15-000013.txt | 2015-05-07 16:38:05 | |
 0000860413-15-000013-xbrl.zip | 314287 | 2015-05-07 16:38:05 |
| fibk-20150331.xml | 3587360 | 2015-05-07 16:38:05 |
| fibk-20150331.xsd | 55948 | 2015-05-07 16:38:05 |
| fibk-20150331x10q.htm | 2055795 | 2015-05-07 16:38:05 |
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| fibk-20150331xex32.htm | 4884 | 2015-05-07 16:38:05 |
| fibk-20150331_cal.xml | 144398 | 2015-05-07 16:38:05 |
| fibk-20150331_def.xml | 447402 | 2015-05-07 16:38:05 |
| fibk-20150331_lab.xml | 899266 | 2015-05-07 16:38:05 |
| fibk-20150331_pre.xml | 540633 | 2015-05-07 16:38:05 |
| FilingSummary.xml | 30146 | 2015-05-07 16:38:05 |
| Financial_Report.xls | 2820293 | 2015-05-07 16:38:05 |
| Financial_Report.xlsx | 318399 | 2015-05-07 16:38:05 |
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| report.css | 2740 | 2015-05-07 16:38:05 |
| Show.js | 1410 | 2015-05-07 16:38:05 |