I want to Make a Documentary

I’ve seen quite a few “one-crew” documentaries, which is basically just one man/woman with a camera, doing their thing.

Anyone have any idea exactly what kind of equipment would be used in such a case in order to achieve the high quality that many of these films show? I don’t know much about cameras, so I’m assuming its something a little more than your standard camcorder but something several orders smaller than those honking big cameras they seem to use for TV remotes and such.