In 1998 I created a prototypeof what was to become XBRL. Since that time I have created more XML using my favorite application as I say, Microsoft Notepad (actually I prefer Ultra Edit), than I actually care to think about. I still have a copy of that prototype.
There probably will not be many takers, but for those who like details, here is a deep dive into XBRL. I took the summary pages I worked with and organized them in one spot to make them easier to find. Here is that list:
The end result of all this is summarized in the document Understanding SEC XBRL Financial Filings. There are two other summaries. The FRUX book and XBRL for Dummies.