Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2012 segment	Aug. 31, 2011	May 31, 2012
Disclosures related to operating segments
Number of Operating Segments	4
Revenue	$ 1,051,325	$ 1,017,180
Income before income taxes	122,773	111,605
Total assets	4,152,235	4,127,892	4,160,906
Rental Uniforms and Ancillary Products [Member]
Disclosures related to operating segments
Revenue	754,843	719,423
Income before income taxes	116,907	99,418
Total assets	2,774,417	2,761,317
Uniform Direct Sales [Member]
Disclosures related to operating segments
Revenue	100,279	101,702
Income before income taxes	8,741	8,407
Total assets	125,094	150,228
First Aid, Safety and Fire Protection [Member]
Disclosures related to operating segments
Revenue	110,841	103,743
Income before income taxes	9,021	8,383
Total assets	359,387	363,692
Document Management [Member]
Disclosures related to operating segments
Revenue	85,362	92,312
Income before income taxes	4,625	12,366
Total assets	563,172	575,615
Corporate [Member]
Disclosures related to operating segments
Revenue	0	0
Income before income taxes	(16,521)	(16,969)
Total assets	$ 330,165	$ 277,040