There are different variations of idealism. Berkely's idealism does indeed makes the claim that nothing can exist without a mind to perceive it. But he was a Christian, and to him God was the supreme mind, and that is how things remained consistent and in place.
As for me, I believe that the universe itself, taken as a whole, is mental. Call it a God or whatever you want to call it. However, it would not cease to exist if I stop perceiving it. It exists, because it itself is also a mind. What I see, hear and feel when I interact with the world is only a representation of that mind, an image, but not the thing-in-itself.
By the way, if you feel that we're only arguing semantics here, then that's because most of philosophy amounts to that.