Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000046619-22-000030-index-headers.html | 2022-05-25 16:21:57 | |
| 0000046619-22-000030-index.html | 2022-05-25 16:21:57 | |
| 0000046619-22-000030.txt | 2022-05-25 16:21:57 | |
 0000046619-22-000030-xbrl.zip | 322594 | 2022-05-25 16:21:57 |
| a43022exhibit101.htm | 622795 | 2022-05-25 16:21:57 |
| a43022exhibit311.htm | 9721 | 2022-05-25 16:21:57 |
| a43022exhibit312.htm | 9703 | 2022-05-25 16:21:57 |
| a43022exhibit321.htm | 5329 | 2022-05-25 16:21:57 |
| a43022exhibit322.htm | 5411 | 2022-05-25 16:21:57 |
| FilingSummary.xml | 35367 | 2022-05-25 16:21:57 |
| Financial_Report.xlsx | 83577 | 2022-05-25 16:21:57 |
| hei-20220430.htm | 1656952 | 2022-05-25 16:21:57 |
| hei-20220430.xsd | 43932 | 2022-05-25 16:21:57 |
| hei-20220430_cal.xml | 71649 | 2022-05-25 16:21:57 |
| hei-20220430_def.xml | 327959 | 2022-05-25 16:21:57 |
| hei-20220430_htm.xml | 1502602 | 2022-05-25 16:21:57 |
| hei-20220430_lab.xml | 561126 | 2022-05-25 16:21:57 |
| hei-20220430_pre.xml | 393487 | 2022-05-25 16:21:57 |
| MetaLinks.json | 603368 | 2022-05-25 16:21:57 |
| R1.htm | 60870 | 2022-05-25 16:21:57 |
| R10.htm | 7905 | 2022-05-25 16:21:57 |
| R11.htm | 46091 | 2022-05-25 16:21:57 |
| R12.htm | 47793 | 2022-05-25 16:21:57 |
| R13.htm | 11591 | 2022-05-25 16:21:57 |
| R14.htm | 73817 | 2022-05-25 16:21:57 |
| R15.htm | 8728 | 2022-05-25 16:21:57 |
| R16.htm | 69995 | 2022-05-25 16:21:57 |
| R17.htm | 25544 | 2022-05-25 16:21:57 |
| R18.htm | 63493 | 2022-05-25 16:21:57 |
| R19.htm | 14671 | 2022-05-25 16:21:57 |
| R2.htm | 147238 | 2022-05-25 16:21:57 |
| R20.htm | 10563 | 2022-05-25 16:21:57 |
| R21.htm | 53281 | 2022-05-25 16:21:57 |
| R22.htm | 50694 | 2022-05-25 16:21:57 |
| R23.htm | 13876 | 2022-05-25 16:21:57 |
| R24.htm | 74090 | 2022-05-25 16:21:57 |
| R25.htm | 67880 | 2022-05-25 16:21:57 |
| R26.htm | 24829 | 2022-05-25 16:21:57 |
| R27.htm | 62403 | 2022-05-25 16:21:57 |
| R28.htm | 11432 | 2022-05-25 16:21:57 |
| R29.htm | 20118 | 2022-05-25 16:21:57 |
| R3.htm | 18824 | 2022-05-25 16:21:57 |
| R30.htm | 10485 | 2022-05-25 16:21:57 |
| R31.htm | 12137 | 2022-05-25 16:21:57 |
| R32.htm | 18624 | 2022-05-25 16:21:57 |
| R33.htm | 6314 | 2022-05-25 16:21:57 |
| R34.htm | 13371 | 2022-05-25 16:21:57 |
| R35.htm | 20631 | 2022-05-25 16:21:57 |
| R36.htm | 24656 | 2022-05-25 16:21:57 |
| R37.htm | 19400 | 2022-05-25 16:21:57 |
| R38.htm | 36850 | 2022-05-25 16:21:57 |
| R39.htm | 23721 | 2022-05-25 16:21:57 |
| R4.htm | 88519 | 2022-05-25 16:21:57 |
| R40.htm | 13039 | 2022-05-25 16:21:57 |
| R41.htm | 5643 | 2022-05-25 16:21:57 |
| R42.htm | 16193 | 2022-05-25 16:21:57 |
| R43.htm | 31598 | 2022-05-25 16:21:57 |
| R44.htm | 28995 | 2022-05-25 16:21:57 |
| R45.htm | 17951 | 2022-05-25 16:21:57 |
| R46.htm | 6635 | 2022-05-25 16:21:57 |
| R47.htm | 27858 | 2022-05-25 16:21:57 |
| R48.htm | 69721 | 2022-05-25 16:21:57 |
| R49.htm | 21174 | 2022-05-25 16:21:57 |
| R5.htm | 45682 | 2022-05-25 16:21:57 |
| R50.htm | 107394 | 2022-05-25 16:21:57 |
| R51.htm | 40645 | 2022-05-25 16:21:57 |
| R52.htm | 36687 | 2022-05-25 16:21:57 |
| R53.htm | 19052 | 2022-05-25 16:21:57 |
| R54.htm | 9625 | 2022-05-25 16:21:57 |
| R55.htm | 4506 | 2022-05-25 16:21:57 |
| R6.htm | 121219 | 2022-05-25 16:21:57 |
| R7.htm | 3065 | 2022-05-25 16:21:57 |
| R8.htm | 91597 | 2022-05-25 16:21:57 |
| R9.htm | 8942 | 2022-05-25 16:21:57 |
| report.css | 2767 | 2022-05-25 16:21:57 |
| Show.js | 1085 | 2022-05-25 16:21:57 |