XBRL 2.1 Specification Change

This article was originally posted on the XBRL Cloud blog.

In a somewhat surprising move, XBRL International has recently promoted an XBRL 2.1 errata to RECOMMENDATION status that just-barely changes the behavior of XBRL (see the April XII Instances). The change is related to the way XBRL performs calculations (and thereby determines "inconsistencies").

Generally, errata aren't even worth mentioning outside the sphere of the XBRL geeks. Errata are most often used to clarify the specification--especially if vendors have different interpretations.

XBRL International has admirably gone to great lengths to keep XBRL 2.1 stable to make adoption possible. Therefore, errata have not heretofore been used to change specifications. To be completely fair, the proposed change is more likely to execute calculations as a "normal" person (read accountant) might expect.

The downside of this change is that nobody in the technical community is 100% sure what the side effects might be for, say, HMRC or SEC filings. The general consensus (but not scientifically proven) is that there will be no practical effects of these changes.

Nonetheless, this note is just a heads up in case you find that a document that previously validated does not, or that your new document is unexpectedly generating inconsistencies.