Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2011 segment year	Aug. 31, 2010	May 31, 2011
Segment Information
Number of operating segments	4
Disclosures related to operating segments
Total revenue	$ 1,017,180	$ 923,904
Income before income taxes	111,605	88,550
Total assets	4,127,892	3,890,904	4,351,940
Rental Uniforms and Ancillary Products
Disclosures related to operating segments
Total revenue	719,423	657,564
Income before income taxes	99,418	78,218
Total assets	2,555,234	2,407,268
Uniform Direct Sales
Disclosures related to operating segments
Total revenue	101,702	98,780
Income before income taxes	8,407	9,847
Total assets	356,311	221,053
First Aid, Safety and Fire Protection
Disclosures related to operating segments
Total revenue	103,743	93,534
Income before income taxes	8,383	3,778
Total assets	363,692	347,281
Document Management
Disclosures related to operating segments
Total revenue	92,312	74,026
Income before income taxes	12,366	8,403
Total assets	575,615	545,853
Corporate
Disclosures related to operating segments
Income before income taxes	(16,969)	(11,696)
Total assets	$ 277,040	$ 369,449