I believe that I have done the work necessary to finally convince myself that XBRL Formula processors are inter operable. I had my doubts for the past three years; but it seems that most of the interoperability issues I was running up against were due to (a) my lack of technical skills (b) poor validation messages from software (c) inconsistent validation messages (d) a few missing conformance suite tests.
As such, I can say that I have personally run or had someone else I know and trust run my reference implementation through the following XBRL processors and each return no validation errors and otherwise appear to provide exactly the same results:
- UBmatrix XPE (4.0)
- XBRL Cloud (web service)
- XBRL Cloud (XRun)
- DecisionSoft TrueNorth
- Reporting Standards
- Arelle (Open Source XBRL processor)
(If there are any other XBRL processors out there which also have XBRL Formula processing capabilities, please contact me and I would gladly test to see if your results are consistent with the results above.)
The reference implementation (of an SEC XBRL financial filing) is very comprehensive and built to exercise XBRL processors. I have 122 assertions which exercise every computation in the XBRL instance plus other business rules. I have working prototypes of US GAAP Domain level, Industry/Activity level, reporting entity level, and reportability/consistency business rules.
I hold these XBRL Formula example files out as excellent examples of how to construct business rules which are necessary to support and prove that you have correctly created your XBRL taxonomy and XBRL instance. These XBRL Formulas are the "glue" which hold your digital financial report together. If you look at the Verification Summary of the XBRL Cloud Evidence Package it is hard to dispute that these business rules are necessary to make sure something like an SEC XBRL financial filings is created correctly. Well, I guess you can always eye-ball this and manually check to see if you got all this stuff correct; but it has been my experience that manually testing this does not work out so well. Automated testing using business rules expressed using XBRL Formula is much more effective and efficient.
There is one specific enhancement to these XBRL Formulas worth pointing out. I am now using the very handy <msg:message>, be sure to take a look at that. You can see examples in this file.
If you want to experiment with XBRL Formulas and you are persistent, try the Arelle XBRL processor. It is open source, totally free.
I predict that 2013 will be the year people start to understand business rules. Get a jump on the herd! Start learning about business rules now. Don't believe that business users are ever going to have to deal with all that ugly XBRL Formula syntax. They won't. But they will need business rules to get their filings correct.