Acquisitions (Details)	12 Months Ended
	May 31, 2012 segment	May 31, 2011 segment
Rental Uniforms and Ancillary Products [Member]
Business Acquisition [Line Items]
Number of businesses acquired	2	4
First Aid, Safety and Fire Protection [Member]
Business Acquisition [Line Items]
Number of businesses acquired	2	11
Document Management [Member]
Business Acquisition [Line Items]
Number of businesses acquired	4	12