Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000067716-17-000042-index-headers.html | 2017-05-08 09:43:52 | |
| 0000067716-17-000042-index.html | 2017-05-08 09:43:52 | |
| 0000067716-17-000042.txt | 2017-05-08 09:43:52 | |
 0000067716-17-000042-xbrl.zip | 250566 | 2017-05-08 09:43:52 |
| a2017q1ex10a.htm | 971221 | 2017-05-08 09:43:52 |
| a2017q1ex10b.htm | 24045 | 2017-05-08 09:43:52 |
| a2017q1ex12.htm | 36695 | 2017-05-08 09:43:52 |
| a2017q1ex31a.htm | 9814 | 2017-05-08 09:43:52 |
| a2017q1ex31b.htm | 9237 | 2017-05-08 09:43:52 |
| a2017q1ex32.htm | 6449 | 2017-05-08 09:43:52 |
| a2017q1ex95.htm | 92186 | 2017-05-08 09:43:52 |
| a2017q1form10-q.htm | 1352073 | 2017-05-08 09:43:52 |
| FilingSummary.xml | 36392 | 2017-05-08 09:43:52 |
| Financial_Report.xlsx | 86633 | 2017-05-08 09:43:52 |
| mdu-20170331.xml | 2003559 | 2017-05-08 09:43:52 |
| mdu-20170331.xsd | 57056 | 2017-05-08 09:43:52 |
| mdu-20170331_cal.xml | 126287 | 2017-05-08 09:43:52 |
| mdu-20170331_def.xml | 386010 | 2017-05-08 09:43:52 |
| mdu-20170331_lab.xml | 792550 | 2017-05-08 09:43:52 |
| mdu-20170331_pre.xml | 469508 | 2017-05-08 09:43:52 |
| R1.htm | 20517 | 2017-05-08 09:43:52 |
| R10.htm | 7872 | 2017-05-08 09:43:52 |
| R11.htm | 24061 | 2017-05-08 09:43:52 |
| R12.htm | 15523 | 2017-05-08 09:43:52 |
| R13.htm | 21482 | 2017-05-08 09:43:52 |
| R14.htm | 87713 | 2017-05-08 09:43:52 |
| R15.htm | 160263 | 2017-05-08 09:43:52 |
| R16.htm | 86819 | 2017-05-08 09:43:52 |
| R17.htm | 130255 | 2017-05-08 09:43:52 |
| R18.htm | 40773 | 2017-05-08 09:43:52 |
| R19.htm | 21977 | 2017-05-08 09:43:52 |
| R2.htm | 84823 | 2017-05-08 09:43:52 |
| R20.htm | 82574 | 2017-05-08 09:43:52 |
| R21.htm | 36937 | 2017-05-08 09:43:52 |
| R22.htm | 22865 | 2017-05-08 09:43:52 |
| R23.htm | 59592 | 2017-05-08 09:43:52 |
| R24.htm | 6398 | 2017-05-08 09:43:52 |
| R25.htm | 22648 | 2017-05-08 09:43:52 |
| R26.htm | 13781 | 2017-05-08 09:43:52 |
| R27.htm | 86870 | 2017-05-08 09:43:52 |
| R28.htm | 153771 | 2017-05-08 09:43:52 |
| R29.htm | 83113 | 2017-05-08 09:43:52 |
| R3.htm | 44142 | 2017-05-08 09:43:52 |
| R30.htm | 127907 | 2017-05-08 09:43:52 |
| R31.htm | 36294 | 2017-05-08 09:43:52 |
| R32.htm | 20655 | 2017-05-08 09:43:52 |
| R33.htm | 74550 | 2017-05-08 09:43:52 |
| R34.htm | 33455 | 2017-05-08 09:43:52 |
| R35.htm | 28960 | 2017-05-08 09:43:52 |
| R36.htm | 7119 | 2017-05-08 09:43:52 |
| R37.htm | 19139 | 2017-05-08 09:43:52 |
| R38.htm | 12579 | 2017-05-08 09:43:52 |
| R39.htm | 8068 | 2017-05-08 09:43:52 |
| R4.htm | 15669 | 2017-05-08 09:43:52 |
| R40.htm | 35271 | 2017-05-08 09:43:52 |
| R41.htm | 32314 | 2017-05-08 09:43:52 |
| R42.htm | 9439 | 2017-05-08 09:43:52 |
| R43.htm | 29795 | 2017-05-08 09:43:52 |
| R44.htm | 16518 | 2017-05-08 09:43:52 |
| R45.htm | 98440 | 2017-05-08 09:43:52 |
| R46.htm | 9513 | 2017-05-08 09:43:52 |
| R47.htm | 14773 | 2017-05-08 09:43:52 |
| R48.htm | 42171 | 2017-05-08 09:43:52 |
| R49.htm | 28452 | 2017-05-08 09:43:52 |
| R5.htm | 120943 | 2017-05-08 09:43:52 |
| R50.htm | 35633 | 2017-05-08 09:43:52 |
| R51.htm | 7309 | 2017-05-08 09:43:52 |
| R52.htm | 18288 | 2017-05-08 09:43:52 |
| R53.htm | 62066 | 2017-05-08 09:43:52 |
| R54.htm | 10938 | 2017-05-08 09:43:52 |
| R55.htm | 45685 | 2017-05-08 09:43:52 |
| R56.htm | 12134 | 2017-05-08 09:43:52 |
| R57.htm | 45871 | 2017-05-08 09:43:52 |
| R58.htm | 32151 | 2017-05-08 09:43:52 |
| R59.htm | 127647 | 2017-05-08 09:43:52 |
| R6.htm | 11170 | 2017-05-08 09:43:52 |
| R60.htm | 4751 | 2017-05-08 09:43:52 |
| R61.htm | 25486 | 2017-05-08 09:43:52 |
| R62.htm | 22723 | 2017-05-08 09:43:52 |
| R63.htm | 71304 | 2017-05-08 09:43:52 |
| R64.htm | 11774 | 2017-05-08 09:43:52 |
| R7.htm | 83729 | 2017-05-08 09:43:52 |
| R8.htm | 8857 | 2017-05-08 09:43:52 |
| R9.htm | 5759 | 2017-05-08 09:43:52 |
| report.css | 2767 | 2017-05-08 09:43:52 |
| Show.js | 1410 | 2017-05-08 09:43:52 |