ivory tower 
noun
A state of privileged seclusion or separation from the facts and practicalities of the real world: the ivory tower of academia...
- Robbie Johnson had cornered a timid young lecturer and was educating him about the nature of the real world outside the ivory tower.
- Rhythm and movement are everywhere in India, like air and water, and affect even the most prosaic shopkeeper in the bazaar or the academic in his ivory tower.
- I'm not going to an ivory tower to write reports and articles for other academics.
Derivatives
ivory-towered
ivory-towerish
Origin
Early 20th century: translating French tour d'ivoire, used by the writer Sainte-Beuve.