The most important aspect of XBRL is its ability to structure information. If you don't understand that, please watch the video, How XBRL Works. Before XBRL, information was unstructured; with XBRL, information is structured and the structure can be leveraged.
Imagine financial reports as pivot tables on steroids. Look at the graphics below and think about the relations between the facts reported within an XBRL-based digital financial report. In particular, have a look at the last three graphics. (Another view of the same information below.)
Imagine not only being able to get and pivot information within one financial report, but also being able to query across periods for the same reporting entity or across entities. You can see such queries, although not dynamic, in these examples.
What technology challenges stands between where we are and the pivot tables you might be able to imagine? None really. The only challenge is providing professional accountants that create these reports with appropriate software tools that allow them to create XBRL-based structured financial reports effectively (i.e. no quality issues) and efficiently.