Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012 segment	Nov. 30, 2011	May 31, 2012
Disclosures related to operating segments
Number of Operating Segments			4
Revenue	$ 1,060,386	$ 1,019,126	$ 2,111,711	$ 2,036,306
Income before income taxes	122,878	115,360	245,651	226,965
Total assets	4,217,882	4,215,312	4,217,882	4,215,312	4,160,906
Rental Uniforms and Ancillary Products [Member]
Disclosures related to operating segments
Revenue	755,839	722,789	1,510,682	1,442,212
Income before income taxes	116,051	104,477	232,958	203,895
Total assets	2,813,707	2,803,231	2,813,707	2,803,231
Uniform Direct Sales [Member]
Disclosures related to operating segments
Revenue	110,203	111,946	210,482	213,648
Income before income taxes	10,404	13,242	19,145	21,649
Total assets	143,880	157,339	143,880	157,339
First Aid, Safety and Fire Protection [Member]
Disclosures related to operating segments
Revenue	111,513	101,687	222,354	205,430
Income before income taxes	9,654	8,962	18,675	17,345
Total assets	393,429	364,461	393,429	364,461
Document Management [Member]
Disclosures related to operating segments
Revenue	82,831	82,704	168,193	175,016
Income before income taxes	2,914	6,004	7,539	18,370
Total assets	590,517	552,676	590,517	552,676
Corporate [Member]
Disclosures related to operating segments
Revenue	0	0	0	0
Income before income taxes	(16,145)	(17,325)	(32,666)	(34,294)
Total assets	$ 276,349	$ 337,605	$ 276,349	$ 337,605