Earnings per Share (Computation of Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	May 31, 2014		Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2014	May 31, 2013	May 31, 2012
Diluted Earnings per Share
Net income	$ 127,224	[1]	$ 84,602	$ 84,862	$ 77,754	$ 85,977	$ 74,705	$ 78,027	$ 76,733	$ 374,442	$ 315,442	$ 297,637
Less: net income allocated to participating unvested securities										3,452	1,896	1,880
Net income available to common shareholders										$ 370,990	$ 313,546	$ 295,757
Basic weighted average common shares outstanding (shares)	119,541	[1]	119,913	119,907	122,130	122,392	123,120	124,185	126,110	120,377	123,956	129,891
Effect of dilutive securities - employee stock options (shares)										1,263	575	142
Diluted weighted average common shares outstanding (shares)										121,640	124,531	130,033
Diluted earnings per share:
Diluted earnings per share (dollars per share)	$ 1.03	[1]	$ 0.69	$ 0.70	$ 0.63	$ 0.69	$ 0.60	$ 0.63	$ 0.60	$ 3.05	$ 2.52	$ 2.27

[1] On April 30, 2014, Cintas completed its previously announced partnership transaction with the shareholders of Shred-it to combine Cintas’ document destruction business with Shred-it’s document destruction business. Under the agreement, Cintas and Shred-it each contributed its document destruction business to a newly formed partnership owned 42% by Cintas and 58% by the shareholders of Shred-it. The deconsolidation of the document destruction business negatively impacted fiscal 2014 fourth quarter revenue. In the fourth quarter of fiscal 2014, the Company realized a $106.4 million gain on deconsolidation of the shredding business. In addition, as a result of the shredding transaction, the Company recorded an asset impairment charge of $16.1 million in the fourth quarter of fiscal 2014. The Company also recorded transaction costs of $28.5 million, of which $2.2 million was recorded in the third quarter and $26.3 million was recorded in the fourth quarter. Please see Note 9 entitled Acquisitions and Deconsolidation for additional information on the transaction.