Is there an open source dialog management platform that is well documented and can be integrated with other components?
This really depends on your definition of dialog management. I’m not aware of any engine that can follow and maintain conversations over a long period of time. However, I thinkBruce Wilcox‘ ChatScript engine is probably what you’re looking for. It has won theLoebner Prize Turing test quite a few times, including again in 2015 (for details seebrilligunderstanding.com). Otherwise, I would suggest looking at Rob Ellis’ (silentrob.me) SuperScript.
See also the list of dialog system APIs listed under my Quora question: