When a leading national restaurant chain and a leading software vendor combine forces to produce an SEC filing, we'd expect an outstanding work product, right? Not in this example.
First, a simple validation routine in Workiva's software would reveal that Luby's cash flow statement doesn't add up against their specified taxonomy. My guess is that the software does the validation, but doesn't require the correction. That doesn't let Luby's off the hook; it's their filing and their responsibility.
Second, unless Luby's has become a bank or insurance company, they're using tags from the wrong US-GAAP taxonomy. This may not seem like a big deal unless you try to compare Luby's results with other restaurants, for example.
Sadly, this is par for the course with XBRL filings. Insufficient attention is paid to the details. Considering that a major reason for requiring companies to file using XBRL is comparability, every stakeholder should work to ensure that this goal is achieved. That means greater care by the company, more robust software and better enforcement by the SEC. This is accounting, not rocket science, and users shouldn't have to fix the data before using it.