Automator script to save MS Word files to newer version

How can I create a Mac OS X (10.9.3) Automator script or workflow that will allow me to open MS Word (2004) files (.doc) and save them as MS Word (2011) files? I have perhaps several thousand files in many different folders. Is there a way to drag a folder onto some window and tell it to open them all or one at a time and save them as .docx files? I've been working for hours and still have thousands to go. Any help would be greatly appreciated. Frank
