The New Testament isn't really a historical document. Its mostly letters dealing with issues within Christianity that you can glean a little history from.

As for the Old Testament, its pretty good historical document since it lines up with archeology fairly well during the Assyrian, Babylonian periods, and early Persian periods. Before that evidence is a little sparse. :-\

Just look at all the stuff that corroberates that part of the Old Testament including the things that it brought up that were unknown in any other source but were confirmed by evidence that has been found within the last 200 years.