This tidbit comes from local news in Denver. No mention of what the incident actually was.http://www.9news.com/story/news/local/2015/08/28/fighter-jets-escort-plane-to-dia-after-disturbance/71351196/
Track of the flight with divert, courtesy FlightAware:http://flightaware.com/live/flight/CFG83/history/20150828/2130Z/KLAS/EDDF
I'm combing through the ATC archives now, but there isn't much coverage of ZLC (Salt Lake) or ZDV (Denver) where the divert happened -- that's the far reaches for both of those centers, so I don't expect to hear much of the original incident, but if I'm lucky I'll get some of the traffic as they approach Denver.
And now the Saturday-morning quarterbacking and thoughts... It couldn't have been immediately urgent. Closest airport with significant commercial service to the point of divert was my home airport, Billings Logan (KBIL), which has been known to handle diverts. The only reasons I can think of are that it's a) a station for Lufthansa, which Condor still has an interline agreement with, and more facilities in case the aircraft had to remain longer; and b) it vectors the aircraft closer to the F16 hardware sent to escort from Buckley AFB (KBKF). Not that it really matters, just observations.