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| 0000003499-21-000009-index.html | 2021-05-03 08:16:46 | |
| 0000003499-21-000009.txt | 2021-05-03 08:16:46 | |
 0000003499-21-000009-xbrl.zip | 172180 | 2021-05-03 08:16:46 |
| alx-20210331.htm | 748978 | 2021-05-03 08:16:46 |
| alx-20210331.xsd | 36418 | 2021-05-03 08:16:46 |
| alx-20210331_cal.xml | 53296 | 2021-05-03 08:16:46 |
| alx-20210331_def.xml | 180159 | 2021-05-03 08:16:46 |
| alx-20210331_htm.xml | 551836 | 2021-05-03 08:16:46 |
| alx-20210331_lab.xml | 416230 | 2021-05-03 08:16:46 |
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| exhibit15-10q33121.htm | 2883 | 2021-05-03 08:16:46 |
| exhibit311-10q33121.htm | 8882 | 2021-05-03 08:16:46 |
| exhibit312-10q33121.htm | 8898 | 2021-05-03 08:16:46 |
| exhibit321-10q33121.htm | 5059 | 2021-05-03 08:16:46 |
| exhibit322-10q33121.htm | 5012 | 2021-05-03 08:16:46 |
| FilingSummary.xml | 25770 | 2021-05-03 08:16:46 |
| Financial_Report.xlsx | 56337 | 2021-05-03 08:16:46 |
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| R1.htm | 52216 | 2021-05-03 08:16:46 |
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| R9.htm | 76070 | 2021-05-03 08:16:46 |
| report.css | 2767 | 2021-05-03 08:16:46 |
| Show.js | 1085 | 2021-05-03 08:16:46 |