Integrated reporting is defined on Wikipedia as:
Integrated reporting refers to a holistic and integrated representation of a company’s performance in terms of both financial and non-financial results.
The vision of integrated reporting is described on the http://www.integratedreporting.org/ web site.
One Report: Integrated Reporting for a Sustainable Strategy is a book written by Robert G. Eccles and Michael Krzus which explains in detail what integrated reporting is all about. Chapter 3 of the book talks about XBRL's role in integrated reporting.