In March 2019, the SEC adopted final amendments to its rules which On March 20, 2019, the SEC adopted final rule amendments, in connection with the FAST Act, which have expanded the scope of XBRL tagging requirements to the cover page of Forms 8-K, 10-Q, 10-K, 20-F, and 40-F (annual reports) using Inline XBRL. The cover page tagging will be phased-in beginning in July/August 2019.
Read more from Lou Rohman of Toppan Merrill and Chair of the Data Quality Committee – https://blog.toppanmerrill.com/blog/author/lou-rohman.