It's just a long rebound. On this topic, I am amazed at the general fan's interpretation of the rules. I cringe every time I hear someone yell, "He's over the back!" There is no such rule prohibiting reaching or jumping over someone. A foul only occurs if there is a pushing or blocking call.
I remember being told in Basketball Officiating class in high school is as long as they are not making contact, then it isn't a foul. If the person behind the defender simply jumps straight up and takes the ball over the defenders head, then no foul. But like you said, if he pushes or basically reaches over the defender causing contact then, you make the "over the back" call. It's a touchy call and the only reason I agree with it is if the defender boxes out and is then pushed or reached over not allowing them to rebound.