Add Support For Reading XBRL Files in Pandas

[cancan101]

XBRL (http://en.wikipedia.org/wiki/XBRL) is the standard format for financial filings.

As of 2009, the SEC requires companies to file in XBRL format (http://xbrl.sec.gov/)

[cpcloud]

@cancan101 want to submit a pull request?

superficially this looks like it would not be too hard using, for example, lxml. only thing is dealing with invalid documents (if that even matters, i.e., you could just raise and tell the user to go get a valid XBRL document)

[cancan101]

Arelle is a Python library for reading XBRL.

Some relevant links:

http://arelle.org/documentation/api/ (overview of API)
https://github.com/Arelle/Arelle/blob/master/arelle/ViewFileFactTable.py (example of writing XBRL factTable to CSV)

[jorisvandenbossche]

I personally think this would be out of scope for core pandas, therefore closing this. But it would certainly make for a nice standalone package if someone is interested.