Acquisitions and Deconsolidation (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended				0 Months Ended		12 Months Ended
	May 31, 2014	Feb. 28, 2014	May 31, 2014	May 31, 2013	May 31, 2012	Apr. 30, 2014 Cintas Document Shredding [Member]	Apr. 30, 2014 Shred-it Partnership [Member]	Apr. 30, 2014 Shred-it Partnership [Member]	May 31, 2014 Series of business acquisitions First Aid, Safety and Fire Protection [Member] segment_business	May 31, 2013 Series of business acquisitions First Aid, Safety and Fire Protection [Member] segment_business	May 31, 2014 Series of business acquisitions Document Management [Member] segment_business	May 31, 2013 Series of business acquisitions Document Management [Member] segment_business
Business Acquisition [Line Items]
Number of businesses acquired									3	3	3	12
Gain (loss) on Shredding deconsolidation			$ 106,441,000	$ 0	$ 0
Contribution to partnership, consideration expected to be received, cash							180,000,000
Equity method investment, recorded at fair value								339,400,000
Carrying amount of business segment						413,000,000
Shredding transaction asset impairment charge			16,143,000	0	0
Shredding transaction costs	26,300,000	2,200,000	28,481,000	0	0
Professional and legal fees			4,700,000
Employee termination benefit costs			700,000
Share-based compensation related to shares vested as a result of Shredding transaction			12,400,000
Charge for information systems contracts			4,200,000
Incremental profit sharing and employee compensation			$ 6,500,000