Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000110019-22-000004-index-headers.html | 2022-02-28 16:20:14 | |
| 0000110019-22-000004-index.html | 2022-02-28 16:20:14 | |
| 0000110019-22-000004.txt | 2022-02-28 16:20:14 | |
 0000110019-22-000004-xbrl.zip | 207196 | 2022-02-28 16:20:14 |
| FilingSummary.xml | 22958 | 2022-02-28 16:20:14 |
| Financial_Report.xlsx | 68706 | 2022-02-28 16:20:14 |
| MetaLinks.json | 471928 | 2022-02-28 16:20:14 |
| nwp-20211231.htm | 1057598 | 2022-02-28 16:20:14 |
| nwp-20211231.xsd | 29749 | 2022-02-28 16:20:14 |
| nwp-20211231_cal.xml | 52293 | 2022-02-28 16:20:14 |
| nwp-20211231_def.xml | 131180 | 2022-02-28 16:20:14 |
| nwp-20211231_htm.xml | 697146 | 2022-02-28 16:20:14 |
| nwp-20211231_lab.xml | 436184 | 2022-02-28 16:20:14 |
| nwp-20211231_pre.xml | 266472 | 2022-02-28 16:20:14 |
| nwp_20211231xex-311.htm | 10272 | 2022-02-28 16:20:14 |
| nwp_20211231xex-312.htm | 10509 | 2022-02-28 16:20:14 |
| nwp_20211231xex-32.htm | 6529 | 2022-02-28 16:20:14 |
| R1.htm | 51012 | 2022-02-28 16:20:14 |
| R10.htm | 12598 | 2022-02-28 16:20:14 |
| R11.htm | 27331 | 2022-02-28 16:20:14 |
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| R2.htm | 7854 | 2022-02-28 16:20:14 |
| R20.htm | 34688 | 2022-02-28 16:20:14 |
| R21.htm | 12538 | 2022-02-28 16:20:14 |
| R22.htm | 12441 | 2022-02-28 16:20:14 |
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| R24.htm | 28348 | 2022-02-28 16:20:14 |
| R25.htm | 44195 | 2022-02-28 16:20:14 |
| R26.htm | 9700 | 2022-02-28 16:20:14 |
| R27.htm | 7639 | 2022-02-28 16:20:14 |
| R28.htm | 42552 | 2022-02-28 16:20:14 |
| R29.htm | 41580 | 2022-02-28 16:20:14 |
| R3.htm | 57330 | 2022-02-28 16:20:14 |
| R30.htm | 12474 | 2022-02-28 16:20:14 |
| R31.htm | 21329 | 2022-02-28 16:20:14 |
| R32.htm | 29953 | 2022-02-28 16:20:14 |
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| R35.htm | 37001 | 2022-02-28 16:20:14 |
| R36.htm | 9977 | 2022-02-28 16:20:14 |
| R37.htm | 41022 | 2022-02-28 16:20:14 |
| R4.htm | 112467 | 2022-02-28 16:20:14 |
| R5.htm | 20793 | 2022-02-28 16:20:14 |
| R6.htm | 81942 | 2022-02-28 16:20:14 |
| R7.htm | 45586 | 2022-02-28 16:20:14 |
| R8.htm | 36664 | 2022-02-28 16:20:14 |
| R9.htm | 33142 | 2022-02-28 16:20:14 |
| R9999.htm | 14005 | 2022-02-28 16:20:14 |
| report.css | 2767 | 2022-02-28 16:20:14 |
| Show.js | 1085 | 2022-02-28 16:20:14 |