Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0001733998-20-000059-index-headers.html | 2020-11-05 14:45:19 | |
| 0001733998-20-000059-index.html | 2020-11-05 14:45:19 | |
| 0001733998-20-000059.txt | 2020-11-05 14:45:19 | |
 0001733998-20-000059-xbrl.zip | 586428 | 2020-11-05 14:45:19 |
| ex3112020q3ng.htm | 8178 | 2020-11-05 14:45:19 |
| ex3122020q3ng.htm | 8314 | 2020-11-05 14:45:19 |
| ex3132020q3ng.htm | 8184 | 2020-11-05 14:45:19 |
| ex3142020q3ng.htm | 8292 | 2020-11-05 14:45:19 |
| ex3212020q3ng.htm | 5796 | 2020-11-05 14:45:19 |
| ex3222020q3ng.htm | 5814 | 2020-11-05 14:45:19 |
| FilingSummary.xml | 37765 | 2020-11-05 14:45:19 |
| Financial_Report.xlsx | 137684 | 2020-11-05 14:45:19 |
| MetaLinks.json | 770034 | 2020-11-05 14:45:19 |
| nwn-20200930.htm | 3876099 | 2020-11-05 14:45:19 |
| nwn-20200930.xsd | 65986 | 2020-11-05 14:45:19 |
| nwn-20200930_cal.xml | 153534 | 2020-11-05 14:45:19 |
| nwn-20200930_def.xml | 574957 | 2020-11-05 14:45:19 |
 nwn-20200930_g1.jpg | 57055 | 2020-11-05 14:45:19 |
 nwn-20200930_g2.jpg | 38736 | 2020-11-05 14:45:19 |
| nwn-20200930_htm.xml | 3526394 | 2020-11-05 14:45:19 |
| nwn-20200930_lab.xml | 863922 | 2020-11-05 14:45:19 |
| nwn-20200930_pre.xml | 631429 | 2020-11-05 14:45:19 |
| R1.htm | 61538 | 2020-11-05 14:45:19 |
| R10.htm | 42640 | 2020-11-05 14:45:19 |
| R11.htm | 98917 | 2020-11-05 14:45:19 |
| R12.htm | 124282 | 2020-11-05 14:45:19 |
| R13.htm | 169070 | 2020-11-05 14:45:19 |
| R14.htm | 9067 | 2020-11-05 14:45:19 |
| R15.htm | 33601 | 2020-11-05 14:45:19 |
| R16.htm | 82212 | 2020-11-05 14:45:19 |
| R17.htm | 49234 | 2020-11-05 14:45:19 |
| R18.htm | 37926 | 2020-11-05 14:45:19 |
| R19.htm | 20062 | 2020-11-05 14:45:19 |
| R2.htm | 101769 | 2020-11-05 14:45:19 |
| R20.htm | 6157 | 2020-11-05 14:45:19 |
| R21.htm | 20685 | 2020-11-05 14:45:19 |
| R22.htm | 50774 | 2020-11-05 14:45:19 |
| R23.htm | 71225 | 2020-11-05 14:45:19 |
| R24.htm | 66775 | 2020-11-05 14:45:19 |
| R25.htm | 37294 | 2020-11-05 14:45:19 |
| R26.htm | 99256 | 2020-11-05 14:45:19 |
| R27.htm | 42228 | 2020-11-05 14:45:19 |
| R28.htm | 94792 | 2020-11-05 14:45:19 |
| R29.htm | 112667 | 2020-11-05 14:45:19 |
| R3.htm | 166580 | 2020-11-05 14:45:19 |
| R30.htm | 173322 | 2020-11-05 14:45:19 |
| R31.htm | 27718 | 2020-11-05 14:45:19 |
| R32.htm | 80576 | 2020-11-05 14:45:19 |
| R33.htm | 46495 | 2020-11-05 14:45:19 |
| R34.htm | 37191 | 2020-11-05 14:45:19 |
| R35.htm | 17762 | 2020-11-05 14:45:19 |
| R36.htm | 10277 | 2020-11-05 14:45:19 |
| R37.htm | 43107 | 2020-11-05 14:45:19 |
| R38.htm | 52215 | 2020-11-05 14:45:19 |
| R39.htm | 135694 | 2020-11-05 14:45:19 |
| R4.htm | 60057 | 2020-11-05 14:45:19 |
| R40.htm | 31061 | 2020-11-05 14:45:19 |
| R41.htm | 25525 | 2020-11-05 14:45:19 |
| R42.htm | 25015 | 2020-11-05 14:45:19 |
| R43.htm | 57635 | 2020-11-05 14:45:19 |
| R44.htm | 16766 | 2020-11-05 14:45:19 |
| R45.htm | 55192 | 2020-11-05 14:45:19 |
| R46.htm | 22061 | 2020-11-05 14:45:19 |
| R47.htm | 91800 | 2020-11-05 14:45:19 |
| R48.htm | 34740 | 2020-11-05 14:45:19 |
| R49.htm | 81859 | 2020-11-05 14:45:19 |
| R5.htm | 121012 | 2020-11-05 14:45:19 |
| R50.htm | 24801 | 2020-11-05 14:45:19 |
| R51.htm | 102165 | 2020-11-05 14:45:19 |
| R52.htm | 34104 | 2020-11-05 14:45:19 |
| R53.htm | 32654 | 2020-11-05 14:45:19 |
| R54.htm | 16107 | 2020-11-05 14:45:19 |
| R55.htm | 37520 | 2020-11-05 14:45:19 |
| R56.htm | 19363 | 2020-11-05 14:45:19 |
| R57.htm | 26050 | 2020-11-05 14:45:19 |
| R58.htm | 31090 | 2020-11-05 14:45:19 |
| R59.htm | 11756 | 2020-11-05 14:45:19 |
| R6.htm | 30427 | 2020-11-05 14:45:19 |
| R60.htm | 16013 | 2020-11-05 14:45:19 |
| R61.htm | 19419 | 2020-11-05 14:45:19 |
| R62.htm | 50217 | 2020-11-05 14:45:19 |
| R63.htm | 26410 | 2020-11-05 14:45:19 |
| R64.htm | 4734 | 2020-11-05 14:45:19 |
| R65.htm | 28600 | 2020-11-05 14:45:19 |
| R66.htm | 17332 | 2020-11-05 14:45:19 |
| R67.htm | 7700 | 2020-11-05 14:45:19 |
| R68.htm | 62680 | 2020-11-05 14:45:19 |
| R69.htm | 31960 | 2020-11-05 14:45:19 |
| R7.htm | 8697 | 2020-11-05 14:45:19 |
| R70.htm | 98590 | 2020-11-05 14:45:19 |
| R8.htm | 19851 | 2020-11-05 14:45:19 |
| R9.htm | 111713 | 2020-11-05 14:45:19 |
| report.css | 2767 | 2020-11-05 14:45:19 |
| Show.js | 1085 | 2020-11-05 14:45:19 |