What does this phrasal verb mean: 'play off'? Is it an idiom?

Dear Torsten,
could you, please, explain the meaning of the following phrase?

He played Othello off Broadway last year.

As I understand it he played the part of Othello, but I am not sure where, in one of the theatres on Broadway or not.

This means away from the main Broadway area. You would say: At a theatre off Broadway.

Thank you, Alan.