Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000046619-20-000018-index-headers.html | 2020-05-28 16:16:59 | |
| 0000046619-20-000018-index.html | 2020-05-28 16:16:59 | |
| 0000046619-20-000018.txt | 2020-05-28 16:16:59 | |
 0000046619-20-000018-xbrl.zip | 277441 | 2020-05-28 16:16:59 |
| a43020heiexhibit311.htm | 11807 | 2020-05-28 16:16:59 |
| a43020heiexhibit312.htm | 11788 | 2020-05-28 16:16:59 |
| a43020heiexhibit321.htm | 7043 | 2020-05-28 16:16:59 |
| a43020heiexhibit322.htm | 7127 | 2020-05-28 16:16:59 |
| FilingSummary.xml | 40843 | 2020-05-28 16:16:59 |
| Financial_Report.xlsx | 75346 | 2020-05-28 16:16:59 |
| hei-20200430.htm | 2164914 | 2020-05-28 16:16:59 |
| hei-20200430.xsd | 47537 | 2020-05-28 16:16:59 |
| hei-20200430_cal.xml | 93078 | 2020-05-28 16:16:59 |
| hei-20200430_def.xml | 337203 | 2020-05-28 16:16:59 |
| hei-20200430_htm.xml | 1835156 | 2020-05-28 16:16:59 |
| hei-20200430_lab.xml | 593326 | 2020-05-28 16:16:59 |
| hei-20200430_pre.xml | 413486 | 2020-05-28 16:16:59 |
| MetaLinks.json | 622590 | 2020-05-28 16:16:59 |
| R1.htm | 60722 | 2020-05-28 16:16:59 |
| R10.htm | 7372 | 2020-05-28 16:16:59 |
| R11.htm | 69422 | 2020-05-28 16:16:59 |
| R12.htm | 77027 | 2020-05-28 16:16:59 |
| R13.htm | 14745 | 2020-05-28 16:16:59 |
| R14.htm | 114569 | 2020-05-28 16:16:59 |
| R15.htm | 7707 | 2020-05-28 16:16:59 |
| R16.htm | 71464 | 2020-05-28 16:16:59 |
| R17.htm | 43107 | 2020-05-28 16:16:59 |
| R18.htm | 39415 | 2020-05-28 16:16:59 |
| R19.htm | 103682 | 2020-05-28 16:16:59 |
| R2.htm | 107160 | 2020-05-28 16:16:59 |
| R20.htm | 19263 | 2020-05-28 16:16:59 |
| R21.htm | 19137 | 2020-05-28 16:16:59 |
| R22.htm | 77943 | 2020-05-28 16:16:59 |
| R23.htm | 76146 | 2020-05-28 16:16:59 |
| R24.htm | 17022 | 2020-05-28 16:16:59 |
| R25.htm | 112454 | 2020-05-28 16:16:59 |
| R26.htm | 70513 | 2020-05-28 16:16:59 |
| R27.htm | 44336 | 2020-05-28 16:16:59 |
| R28.htm | 38639 | 2020-05-28 16:16:59 |
| R29.htm | 102547 | 2020-05-28 16:16:59 |
| R3.htm | 18135 | 2020-05-28 16:16:59 |
| R30.htm | 17111 | 2020-05-28 16:16:59 |
| R31.htm | 6705 | 2020-05-28 16:16:59 |
| R32.htm | 16675 | 2020-05-28 16:16:59 |
| R33.htm | 10444 | 2020-05-28 16:16:59 |
| R34.htm | 12104 | 2020-05-28 16:16:59 |
| R35.htm | 19500 | 2020-05-28 16:16:59 |
| R36.htm | 6066 | 2020-05-28 16:16:59 |
| R37.htm | 13368 | 2020-05-28 16:16:59 |
| R38.htm | 20579 | 2020-05-28 16:16:59 |
| R39.htm | 13130 | 2020-05-28 16:16:59 |
| R4.htm | 70728 | 2020-05-28 16:16:59 |
| R40.htm | 17270 | 2020-05-28 16:16:59 |
| R41.htm | 36378 | 2020-05-28 16:16:59 |
| R42.htm | 23610 | 2020-05-28 16:16:59 |
| R43.htm | 12992 | 2020-05-28 16:16:59 |
| R44.htm | 5626 | 2020-05-28 16:16:59 |
| R45.htm | 15611 | 2020-05-28 16:16:59 |
| R46.htm | 31390 | 2020-05-28 16:16:59 |
| R47.htm | 28915 | 2020-05-28 16:16:59 |
| R48.htm | 17913 | 2020-05-28 16:16:59 |
| R49.htm | 9184 | 2020-05-28 16:16:59 |
| R5.htm | 40904 | 2020-05-28 16:16:59 |
| R50.htm | 27758 | 2020-05-28 16:16:59 |
| R51.htm | 18034 | 2020-05-28 16:16:59 |
| R52.htm | 12726 | 2020-05-28 16:16:59 |
| R53.htm | 18157 | 2020-05-28 16:16:59 |
| R54.htm | 9813 | 2020-05-28 16:16:59 |
| R55.htm | 9677 | 2020-05-28 16:16:59 |
| R56.htm | 22732 | 2020-05-28 16:16:59 |
| R57.htm | 6752 | 2020-05-28 16:16:59 |
| R58.htm | 6880 | 2020-05-28 16:16:59 |
| R59.htm | 19327 | 2020-05-28 16:16:59 |
| R6.htm | 163497 | 2020-05-28 16:16:59 |
| R60.htm | 35238 | 2020-05-28 16:16:59 |
| R61.htm | 31323 | 2020-05-28 16:16:59 |
| R62.htm | 14576 | 2020-05-28 16:16:59 |
| R63.htm | 11681 | 2020-05-28 16:16:59 |
| R64.htm | 4496 | 2020-05-28 16:16:59 |
| R7.htm | 3049 | 2020-05-28 16:16:59 |
| R8.htm | 88575 | 2020-05-28 16:16:59 |
| R9.htm | 13524 | 2020-05-28 16:16:59 |
| report.css | 2767 | 2020-05-28 16:16:59 |
| Show.js | 1085 | 2020-05-28 16:16:59 |