Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0001193125-18-081603-index-headers.html | 2018-03-14 10:40:09 | |
| 0001193125-18-081603-index.html | 2018-03-14 10:40:09 | |
| 0001193125-18-081603.txt | 2018-03-14 10:40:09 | |
 0001193125-18-081603-xbrl.zip | 362630 | 2018-03-14 10:40:09 |
| d508505d10k.htm | 2864207 | 2018-03-14 10:40:09 |
| d508505dex21.htm | 4726 | 2018-03-14 10:40:09 |
| d508505dex23.htm | 2375 | 2018-03-14 10:40:09 |
| d508505dex311.htm | 9411 | 2018-03-14 10:40:09 |
| d508505dex312.htm | 9427 | 2018-03-14 10:40:09 |
| d508505dex32.htm | 5975 | 2018-03-14 10:40:09 |
| FilingSummary.xml | 87294 | 2018-03-14 10:40:09 |
| Financial_Report.xlsx | 189969 | 2018-03-14 10:40:09 |
| fisi-20171231.xml | 4063801 | 2018-03-14 10:40:09 |
| fisi-20171231.xsd | 101753 | 2018-03-14 10:40:09 |
| fisi-20171231_cal.xml | 181200 | 2018-03-14 10:40:09 |
| fisi-20171231_def.xml | 484379 | 2018-03-14 10:40:09 |
| fisi-20171231_lab.xml | 896721 | 2018-03-14 10:40:09 |
| fisi-20171231_pre.xml | 879628 | 2018-03-14 10:40:09 |
 g508505g0306082008751.jpg | 32800 | 2018-03-14 10:40:09 |
| R1.htm | 28399 | 2018-03-14 10:40:09 |
| R10.htm | 20425 | 2018-03-14 10:40:09 |
| R100.htm | 20756 | 2018-03-14 10:40:09 |
| R101.htm | 24482 | 2018-03-14 10:40:09 |
| R102.htm | 7504 | 2018-03-14 10:40:09 |
| R103.htm | 44887 | 2018-03-14 10:40:09 |
| R104.htm | 27807 | 2018-03-14 10:40:09 |
| R105.htm | 11375 | 2018-03-14 10:40:09 |
| R106.htm | 65319 | 2018-03-14 10:40:09 |
| R107.htm | 24108 | 2018-03-14 10:40:09 |
| R108.htm | 14354 | 2018-03-14 10:40:09 |
| R109.htm | 15473 | 2018-03-14 10:40:09 |
| R11.htm | 205969 | 2018-03-14 10:40:09 |
| R110.htm | 9433 | 2018-03-14 10:40:09 |
| R111.htm | 7051 | 2018-03-14 10:40:09 |
| R112.htm | 28088 | 2018-03-14 10:40:09 |
| R113.htm | 14525 | 2018-03-14 10:40:09 |
| R114.htm | 70063 | 2018-03-14 10:40:09 |
| R115.htm | 20521 | 2018-03-14 10:40:09 |
| R116.htm | 19685 | 2018-03-14 10:40:09 |
| R117.htm | 17175 | 2018-03-14 10:40:09 |
| R118.htm | 75317 | 2018-03-14 10:40:09 |
| R119.htm | 23590 | 2018-03-14 10:40:09 |
| R12.htm | 17560 | 2018-03-14 10:40:09 |
| R120.htm | 46480 | 2018-03-14 10:40:09 |
| R121.htm | 29736 | 2018-03-14 10:40:09 |
| R122.htm | 34803 | 2018-03-14 10:40:09 |
| R123.htm | 57555 | 2018-03-14 10:40:09 |
| R124.htm | 4584 | 2018-03-14 10:40:09 |
| R125.htm | 17528 | 2018-03-14 10:40:09 |
| R126.htm | 41831 | 2018-03-14 10:40:09 |
| R13.htm | 288680 | 2018-03-14 10:40:09 |
| R14.htm | 13602 | 2018-03-14 10:40:09 |
| R15.htm | 38909 | 2018-03-14 10:40:09 |
| R16.htm | 22975 | 2018-03-14 10:40:09 |
| R17.htm | 15668 | 2018-03-14 10:40:09 |
| R18.htm | 32451 | 2018-03-14 10:40:09 |
| R19.htm | 20491 | 2018-03-14 10:40:09 |
| R2.htm | 77326 | 2018-03-14 10:40:09 |
| R20.htm | 77559 | 2018-03-14 10:40:09 |
| R21.htm | 29587 | 2018-03-14 10:40:09 |
| R22.htm | 96928 | 2018-03-14 10:40:09 |
| R23.htm | 41138 | 2018-03-14 10:40:09 |
| R24.htm | 60429 | 2018-03-14 10:40:09 |
| R25.htm | 26765 | 2018-03-14 10:40:09 |
| R26.htm | 178657 | 2018-03-14 10:40:09 |
| R27.htm | 113905 | 2018-03-14 10:40:09 |
| R28.htm | 63750 | 2018-03-14 10:40:09 |
| R29.htm | 53309 | 2018-03-14 10:40:09 |
| R3.htm | 30237 | 2018-03-14 10:40:09 |
| R30.htm | 160006 | 2018-03-14 10:40:09 |
| R31.htm | 18765 | 2018-03-14 10:40:09 |
| R32.htm | 13728 | 2018-03-14 10:40:09 |
| R33.htm | 199968 | 2018-03-14 10:40:09 |
| R34.htm | 13873 | 2018-03-14 10:40:09 |
| R35.htm | 271160 | 2018-03-14 10:40:09 |
| R36.htm | 11474 | 2018-03-14 10:40:09 |
| R37.htm | 30246 | 2018-03-14 10:40:09 |
| R38.htm | 19220 | 2018-03-14 10:40:09 |
| R39.htm | 9104 | 2018-03-14 10:40:09 |
| R4.htm | 117265 | 2018-03-14 10:40:09 |
| R40.htm | 27314 | 2018-03-14 10:40:09 |
| R41.htm | 12340 | 2018-03-14 10:40:09 |
| R42.htm | 58007 | 2018-03-14 10:40:09 |
| R43.htm | 25017 | 2018-03-14 10:40:09 |
| R44.htm | 97608 | 2018-03-14 10:40:09 |
| R45.htm | 30237 | 2018-03-14 10:40:09 |
| R46.htm | 52910 | 2018-03-14 10:40:09 |
| R47.htm | 25251 | 2018-03-14 10:40:09 |
| R48.htm | 143782 | 2018-03-14 10:40:09 |
| R49.htm | 90400 | 2018-03-14 10:40:09 |
| R5.htm | 16976 | 2018-03-14 10:40:09 |
| R50.htm | 61919 | 2018-03-14 10:40:09 |
| R51.htm | 51618 | 2018-03-14 10:40:09 |
| R52.htm | 41251 | 2018-03-14 10:40:09 |
| R53.htm | 22788 | 2018-03-14 10:40:09 |
| R54.htm | 29370 | 2018-03-14 10:40:09 |
| R55.htm | 17190 | 2018-03-14 10:40:09 |
| R56.htm | 12684 | 2018-03-14 10:40:09 |
| R57.htm | 21687 | 2018-03-14 10:40:09 |
| R58.htm | 61787 | 2018-03-14 10:40:09 |
| R59.htm | 9020 | 2018-03-14 10:40:09 |
| R6.htm | 73532 | 2018-03-14 10:40:09 |
| R60.htm | 9213 | 2018-03-14 10:40:09 |
| R61.htm | 56997 | 2018-03-14 10:40:09 |
| R62.htm | 92636 | 2018-03-14 10:40:09 |
| R63.htm | 8668 | 2018-03-14 10:40:09 |
| R64.htm | 13085 | 2018-03-14 10:40:09 |
| R65.htm | 35939 | 2018-03-14 10:40:09 |
| R66.htm | 33348 | 2018-03-14 10:40:09 |
| R67.htm | 54553 | 2018-03-14 10:40:09 |
| R68.htm | 14949 | 2018-03-14 10:40:09 |
| R69.htm | 43924 | 2018-03-14 10:40:09 |
| R7.htm | 10092 | 2018-03-14 10:40:09 |
| R70.htm | 22475 | 2018-03-14 10:40:09 |
| R71.htm | 24991 | 2018-03-14 10:40:09 |
| R72.htm | 55120 | 2018-03-14 10:40:09 |
| R73.htm | 22434 | 2018-03-14 10:40:09 |
| R74.htm | 15338 | 2018-03-14 10:40:09 |
| R75.htm | 17841 | 2018-03-14 10:40:09 |
| R76.htm | 17582 | 2018-03-14 10:40:09 |
| R77.htm | 13389 | 2018-03-14 10:40:09 |
| R78.htm | 4149 | 2018-03-14 10:40:09 |
| R79.htm | 21166 | 2018-03-14 10:40:09 |
| R8.htm | 104631 | 2018-03-14 10:40:09 |
| R80.htm | 10380 | 2018-03-14 10:40:09 |
| R81.htm | 33197 | 2018-03-14 10:40:09 |
| R82.htm | 12107 | 2018-03-14 10:40:09 |
| R83.htm | 10713 | 2018-03-14 10:40:09 |
| R84.htm | 8979 | 2018-03-14 10:40:09 |
| R85.htm | 6046 | 2018-03-14 10:40:09 |
| R86.htm | 10417 | 2018-03-14 10:40:09 |
| R87.htm | 19427 | 2018-03-14 10:40:09 |
| R88.htm | 34964 | 2018-03-14 10:40:09 |
| R89.htm | 80238 | 2018-03-14 10:40:09 |
| R9.htm | 111643 | 2018-03-14 10:40:09 |
| R90.htm | 42144 | 2018-03-14 10:40:09 |
| R91.htm | 38176 | 2018-03-14 10:40:09 |
| R92.htm | 41217 | 2018-03-14 10:40:09 |
| R93.htm | 25037 | 2018-03-14 10:40:09 |
| R94.htm | 40165 | 2018-03-14 10:40:09 |
| R95.htm | 76347 | 2018-03-14 10:40:09 |
| R96.htm | 23385 | 2018-03-14 10:40:09 |
| R97.htm | 32657 | 2018-03-14 10:40:09 |
| R98.htm | 9822 | 2018-03-14 10:40:09 |
| R99.htm | 34653 | 2018-03-14 10:40:09 |
| report.css | 2768 | 2018-03-14 10:40:09 |
| Show.js | 1411 | 2018-03-14 10:40:09 |