Given your reads it's an easy push. I'd say he has something like AdT, or, at worst, QJd . If he had a better hand (like TT or AA) he'd have reraised preflop. If he had a set, he'd try and extract more from the hand.

Logically, he'd expect you to fold any AK (except AKd), any hand other than TT/99/AA (possibly KK). That's a small portion of your raising range.

At worst, you can think of it this way, don't you want to get all-in with hands like this against a maniac?