Hi Elmhurst – each fact tagged in an instance has metadata associated with it – including period details – making the XBRL data standard an excellent mechanism for analysis.
The query below summarizes reporting for the three companies in your post – drop this into the ‘config’ tab as a new row (give it a name), then select it from the Main Sheet dropdown to get results.
/fact/search?concept.local-name=EntityFilerCategory&entity.cik=0001018724,0000320193,0000789019&fields=entity.name,period.fiscal-year.sort(ASC),period.fiscal-period.sort(ASC),period.end,fact.value,report.sec-url,fact.offset(0)
Non-members will need to use the fact.offset(xx) switch to get later details. See #3 here: https://xbrl.us/forums/topic/how-to-get-a-sample-of-records-via-xbrl-api-for-evaluation/#post-116618 or ‘Paging’ in https://xbrl.us/xbrl-api-documentation for details.
The national consortium for 
