It's common, indeed a standard prerequisite for a teaching job in most university-level business schools. Some institutions that grant it use the initials DBA (Doctor of Business Administration), others PhD.

In any case, the term "PhD" in this thread was used in a generic sense for any doctorate in an academic field, not just one with those specific initials. When I got mine, I had a choice between PhD and ScD (Doctor of Science). I picked PhD because more people are familiar with it, but it was my choice after I had passed all the requirements.

What's an "on the line" school, BTW? Is it on a production line? Is your career on the line if you don't graduate? Or did you, perchance, mean "online?"