Yesterday I posted this blog entry which explained how a logical model can be leveraged in working with XBRL.
Here is sample code(an Excel VBA module) which generates the XBRL Formula file from the business rules info set. After you download and run the VBA code which generates the XBRL Formula file, you can run that formula file against this XBRL instanceto run the XBRL Formulas to see that it does, in fact, work. Of course, you will need an XBRL processor which supports XBRL Formula.