Segment Information (Details) $ in Thousands		3 Months Ended
		Aug. 31, 2015 USD ($)	May. 31, 2015 USD ($) segment	Aug. 31, 2014 USD ($)
Segment Reporting Information
Number of operating segments | segment			3
Revenue		$ 1,198,890		$ 1,102,077
Income before income taxes		169,214		168,697
Total assets		4,122,949	$ 4,192,460	4,556,270
Operating Segments | Uniform Rental and Facility Services
Segment Reporting Information
Revenue		938,408		873,698
Income before income taxes		165,381		144,816
Total assets		2,870,622		2,861,790
Operating Segments | First Aid and Safety Services
Segment Reporting Information
Revenue		99,488		79,924
Income before income taxes		8,592		9,147
Total assets		398,237		260,580
Operating Segments | All Other
Segment Reporting Information
Revenue		160,994		148,455
Income before income taxes		11,534		9,525
Total assets		342,712		354,260
Corporate
Segment Reporting Information
Revenue	[1]	0		0
Income before income taxes	[1]	(16,293)		5,209
Total assets	[1]	$ 511,378		$ 1,079,640

[1] Corporate assets as of August 31, 2015 include the investment in Shred-it, which is classified as held for sale. Corporate assets as of August 31, 2014 include the assets of Storage, which was classified as held for sale, and the investment in Shred-it.