replace part of sub folder names, within i main folder, using power shell

Hi all, 

Total newbie here. I have a folder cointaing several hundred sub folders. each of the subfolders starts with the same word, followed by a space, followed by a dash, followed by a sapce, followed by the rest of the sub folder name. For example 'Brick - XXX'

I need to Delete the 'Brick - ' and just leave the XXX.

How do I do this in PowerShell?