I don't know fireworks that well, but these appeared to be the commercial type, with a large lift-charge that lights the sky up with a lightning style flash followed by a sky burst and the house-shaking boom of the sort I usually associate with shows put on the city or whatnot. I had two of these "shows" going on just north of me and one to the south.

And I have a pretty good idea of heights around here. I mentioned I work at Boeing on flying things so I track the ones that fly over me. They're usually about 1000 to 1500 ft. AGL on approach when they go over my house and about 200 knots. Southwest has the most flights into and out of St. Louis so it's usually a 737, and those have a wingspan of just over 100 feet on the newer models.

So yeah, I'd say these fireworks were going up at least 300 feet.