Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000860413-14-000021-index-headers.html | 2014-11-07 16:57:35 | |
| 0000860413-14-000021-index.html | 2014-11-07 16:57:35 | |
| 0000860413-14-000021.txt | 2014-11-07 16:57:35 | |
 0000860413-14-000021-xbrl.zip | 367921 | 2014-11-07 16:57:35 |
| fibk-20140930.xml | 4228455 | 2014-11-07 16:57:35 |
| fibk-20140930.xsd | 69183 | 2014-11-07 16:57:35 |
| fibk-20140930x10q.htm | 2526438 | 2014-11-07 16:57:35 |
| fibk-20140930xex311.htm | 12054 | 2014-11-07 16:57:35 |
| fibk-20140930xex312.htm | 12411 | 2014-11-07 16:57:35 |
| fibk-20140930xex32.htm | 4893 | 2014-11-07 16:57:35 |
| fibk-20140930_cal.xml | 147324 | 2014-11-07 16:57:35 |
| fibk-20140930_def.xml | 493442 | 2014-11-07 16:57:35 |
| fibk-20140930_lab.xml | 1011248 | 2014-11-07 16:57:35 |
| fibk-20140930_pre.xml | 599152 | 2014-11-07 16:57:35 |
| FilingSummary.xml | 34508 | 2014-11-07 16:57:35 |
| Financial_Report.xls | 3394829 | 2014-11-07 16:57:35 |
| Financial_Report.xlsx | 373909 | 2014-11-07 16:57:35 |
| R1.htm | 24996 | 2014-11-07 16:57:35 |
| R10.htm | 83599 | 2014-11-07 16:57:35 |
| R11.htm | 212049 | 2014-11-07 16:57:35 |
| R12.htm | 558191 | 2014-11-07 16:57:35 |
| R13.htm | 185927 | 2014-11-07 16:57:35 |
| R14.htm | 36294 | 2014-11-07 16:57:35 |
| R15.htm | 11740 | 2014-11-07 16:57:35 |
| R16.htm | 16884 | 2014-11-07 16:57:35 |
| R17.htm | 36029 | 2014-11-07 16:57:35 |
| R18.htm | 95111 | 2014-11-07 16:57:35 |
| R19.htm | 14541 | 2014-11-07 16:57:35 |
| R2.htm | 139049 | 2014-11-07 16:57:35 |
| R20.htm | 8086 | 2014-11-07 16:57:35 |
| R21.htm | 12025 | 2014-11-07 16:57:35 |
| R22.htm | 89750 | 2014-11-07 16:57:35 |
| R23.htm | 193844 | 2014-11-07 16:57:35 |
| R24.htm | 8999 | 2014-11-07 16:57:35 |
| R25.htm | 22938 | 2014-11-07 16:57:35 |
| R26.htm | 7643 | 2014-11-07 16:57:35 |
| R27.htm | 76741 | 2014-11-07 16:57:35 |
| R28.htm | 212510 | 2014-11-07 16:57:35 |
| R29.htm | 554388 | 2014-11-07 16:57:35 |
| R3.htm | 19771 | 2014-11-07 16:57:35 |
| R30.htm | 183173 | 2014-11-07 16:57:35 |
| R31.htm | 32939 | 2014-11-07 16:57:35 |
| R32.htm | 31689 | 2014-11-07 16:57:35 |
| R33.htm | 90709 | 2014-11-07 16:57:35 |
| R34.htm | 89759 | 2014-11-07 16:57:35 |
| R35.htm | 180603 | 2014-11-07 16:57:35 |
| R36.htm | 37126 | 2014-11-07 16:57:35 |
| R37.htm | 67068 | 2014-11-07 16:57:35 |
| R38.htm | 7822 | 2014-11-07 16:57:35 |
| R39.htm | 17419 | 2014-11-07 16:57:35 |
| R4.htm | 141562 | 2014-11-07 16:57:35 |
| R40.htm | 11188 | 2014-11-07 16:57:35 |
| R41.htm | 57999 | 2014-11-07 16:57:35 |
| R42.htm | 8754 | 2014-11-07 16:57:35 |
| R43.htm | 13043 | 2014-11-07 16:57:35 |
| R44.htm | 67279 | 2014-11-07 16:57:35 |
| R45.htm | 77739 | 2014-11-07 16:57:35 |
| R46.htm | 29760 | 2014-11-07 16:57:35 |
| R47.htm | 14735 | 2014-11-07 16:57:35 |
| R48.htm | 16348 | 2014-11-07 16:57:35 |
| R49.htm | 113040 | 2014-11-07 16:57:35 |
| R5.htm | 34075 | 2014-11-07 16:57:35 |
| R50.htm | 82671 | 2014-11-07 16:57:35 |
| R51.htm | 60450 | 2014-11-07 16:57:35 |
| R52.htm | 87234 | 2014-11-07 16:57:35 |
| R53.htm | 76451 | 2014-11-07 16:57:35 |
| R54.htm | 18634 | 2014-11-07 16:57:35 |
| R55.htm | 6888 | 2014-11-07 16:57:35 |
| R56.htm | 14008 | 2014-11-07 16:57:35 |
| R57.htm | 30801 | 2014-11-07 16:57:35 |
| R58.htm | 38535 | 2014-11-07 16:57:35 |
| R59.htm | 71032 | 2014-11-07 16:57:35 |
| R6.htm | 55076 | 2014-11-07 16:57:35 |
| R60.htm | 13930 | 2014-11-07 16:57:35 |
| R61.htm | 6649 | 2014-11-07 16:57:35 |
| R62.htm | 8688 | 2014-11-07 16:57:35 |
| R63.htm | 21713 | 2014-11-07 16:57:35 |
| R64.htm | 48013 | 2014-11-07 16:57:35 |
| R65.htm | 13588 | 2014-11-07 16:57:35 |
| R66.htm | 82349 | 2014-11-07 16:57:35 |
| R67.htm | 71429 | 2014-11-07 16:57:35 |
| R68.htm | 9295 | 2014-11-07 16:57:35 |
| R69.htm | 37277 | 2014-11-07 16:57:35 |
| R7.htm | 26780 | 2014-11-07 16:57:35 |
| R70.htm | 5366 | 2014-11-07 16:57:35 |
| R8.htm | 158033 | 2014-11-07 16:57:35 |
| R9.htm | 9862 | 2014-11-07 16:57:35 |
| report.css | 2740 | 2014-11-07 16:57:35 |
| Show.js | 1410 | 2014-11-07 16:57:35 |