What you are doing sounds like the right level of detail. When I take over a project, I like to have an architectural overview so that I have a context to work

What you are doing sounds like the right level of detail. When I take over a project, I like to have an architectural overview so that I have a context to work from. Detailed but wrong is worthless. One important piece that I often find missing is a short narrative about each table in the database. I write short architectural papers as I go along, mostly to get feedback from interested parties. I do the "official" documentation at the end.