On a side note, Orangutans can be found in all-indoor exhibits in these 7 North American zoos: Brookfield (both gorillas and orangs are in Tropic World), Racine, Toronto, Cleveland, Birmingham, Fort Wayne and Pittsburgh. Interestingly enough I cannot think of any all-indoor chimpanzee or bonobo exhibits.
Toronto has plans to build an outdoor orangutan exhibit. As it stands right now, it is the next project to be funded after the Health Centre, which is just starting construction.