How long to wait for a hiring decision

I had an onsite interview, about a week ago. Still waiting for results. I felt I did fine at the interview. It is not my ideal company, but have been job hunting for a while and really need some positive result.

It is a mid size company. Don't know if they are doing background check and other things now. How long does it take for them to offer a job to the first candidate? Anybody knows!

Thanks!