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|---|---|---|
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| 0000080172-19-000018-index.html | 2019-05-10 16:01:39 | |
| 0000080172-19-000018.txt | 2019-05-10 16:01:39 | |
 0000080172-19-000018-xbrl.zip | 68034 | 2019-05-10 16:01:39 |
| FilingSummary.xml | 24011 | 2019-05-10 16:01:39 |
| Financial_Report.xlsx | 41751 | 2019-05-10 16:01:39 |
| npk-20190331.xml | 558903 | 2019-05-10 16:01:39 |
| npk-20190331.xsd | 24966 | 2019-05-10 16:01:39 |
| npk-20190331x10q.htm | 792760 | 2019-05-10 16:01:39 |
| npk-20190331xex31_1.htm | 15360 | 2019-05-10 16:01:39 |
| npk-20190331xex31_2.htm | 15641 | 2019-05-10 16:01:39 |
| npk-20190331xex32_1.htm | 8931 | 2019-05-10 16:01:39 |
| npk-20190331xex32_2.htm | 9128 | 2019-05-10 16:01:39 |
| npk-20190331_cal.xml | 60952 | 2019-05-10 16:01:39 |
| npk-20190331_def.xml | 73716 | 2019-05-10 16:01:39 |
| npk-20190331_lab.xml | 211481 | 2019-05-10 16:01:39 |
| npk-20190331_pre.xml | 194176 | 2019-05-10 16:01:39 |
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| R9.htm | 5054 | 2019-05-10 16:01:39 |
| report.css | 2767 | 2019-05-10 16:01:39 |
| Show.js | 1085 | 2019-05-10 16:01:39 |