I don't know if creating Private Documentations is really what you are after, but I would definitely use this service for hosting private, team-only documentations. Otherwise its a great product, and really easy to get up and running with 👍
I have found this documentation builder a few weeks ago. I created documentation for my API so fast and I must say that my friends & users are very satisfied with obtained result. I would recommend it for a successful API & service documentation builder.