Did I make the correct play?

[POWER13]

I'm holding AdAs in 3rd position (my stack=7500)....UTG (stack=8300) raises BB (300) to 600....I re-raise to 1800. Everyone else folds, UTG guy calls. Flop comes Kh, 7s, 3d. He pushes all-in. I push all in only to lose to his 2 pair....he's holding Kc3c. What do you think of my original raise, should it have been more, or is this guy just a plain idiot? The guy can't be the brightest...but opinions on the raise?