| Form type | Document | Filing | Description | Filing date | Reporting date | File number(s) |
|---|---|---|---|---|---|---|
| 4 | Open Document | Open Filing | FORM 4 | May 5, 2022 | May 3, 2022 | 000-26640 |
| 4 | Open Document | Open Filing | FORM 4 | May 6, 2021 | May 4, 2021 | 000-26640 |
| 4 | Open Document | Open Filing | FORM 4 | May 1, 2020 | Apr 29, 2020 | 000-26640 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | May 3, 2019 | May 1, 2019 | 000-26640 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | May 4, 2018 | May 2, 2018 | 000-26640 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | May 4, 2017 | May 2, 2017 | 000-26640 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | May 6, 2016 | May 4, 2016 | 000-26640 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | Dec 22, 2015 | Dec 21, 2015 | 000-26640 |
| 3 | Open Document | Open Filing | PRIMARY DOCUMENT | Nov 6, 2015 | Oct 28, 2015 | 000-26640 |