| Form type | Document | Filing | Description | Filing date | Reporting date | File number(s) |
|---|---|---|---|---|---|---|
| 4 | Open Document | Open Filing | FORM 4 | May 13, 2021 | May 11, 2021 | 000-18953 |
| 4 | Open Document | Open Filing | FORM 4 | May 13, 2020 | May 12, 2020 | 000-18953 |
| 4 | Open Document | Open Filing | FORM 4 | May 16, 2019 | May 14, 2019 | 000-18953 |
| 4 | Open Document | Open Filing | FORM 4 | May 16, 2018 | May 15, 2018 | 000-18953 |
| 3 | Open Document | Open Filing | FORM 3 | May 19, 2017 | May 16, 2017 | 000-18953 |