The term document is a very ambiguous one and with the militaristic language that our society has started to develop recently, it appears that document can mean far more than just a piece of paper anymore. This is similar to how the term package can be used ambiguously and applied to people take the package over there or I have the package in custody.
If you have a dream of documents then this means that you are thinking about your memories and where you file them away. The mind works in mysterious ways and sometimes you lose information that you were sure you could never forget. Other times you will remember something for ages that you have no need to remember. These documents represent this struggle. You are trying to remember a memory but you aren't sure where you filed it.
A document is different than just a book which can be read over easily, a document is something which requires more attention from you than just that. Therefore if you have a dream in which you are perusing a document then this can mean that there is something that is going to be going on in your life soon which will require a great deal of your attention and your time. If you want to accomplish this with ease and finesse then the best thing for you to do would be to simply think about what you can do to pay closer attention to the things that affect you.