be in an/(one's) ivory tower

To reside or exist in a place or among a social circle that is characterized by effete academic intelligence and thus is out of touch with or aloof from the realities of life. I don't put much weight in the advice of a bunch of economists who are in their ivory towers and have never worked a real job in their lives. It seemed easy to solve all the world's problems when I was in an ivory tower. Now that I'm out of college, I realize things are so much more complex than I'd imagined. I don't care what some professor thinks will improve the education system—he's in his ivory tower while we're on the front lines teaching kids in under-resourced communities!