Honestly, I think Qt's tutorials and documentation are plenty thorough if you're not new to C++. Trolltech/Nokia/Digia/WHOEVER THE HELL IS RUNNING THIS SHIP THESE DAYS has consistently put out good documentation compared to a lot of other projects.
Qt is its own company now. Digia spun them off to better focus on Qt, or something like that.
They do have a lot of information. It's much better then the projects who's doc links point to a Github repo. It could be laid out better though.
I'm thinking they added somethings since I last looked at it, or I was rushing at the time.