I have updated a set of high-quality XBRL instance, XBRL taxonomy, XBRL formula examples that I have been maintaining for probably 15 years now. Each example has been validated using three different XBRL processors and XBRL Formula processors.
The concept arrangement patterns, member arrangement patterns, and business use cases represent individual fragments of a report and help make sure the individual fragments work as expected. The reference implementations take all of the individual fragments, put them TOGETHER into one document, and make sure the document as a whole works properly. These examples are excellent training tools and excellent for software testing.
I consider all of these examples to be public domain. These examples are housed on the Learning about XBRL page of my blog.
Happy learning!