Earnings per Share - Computation of Diluted Earnings Per Share For Continuing Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015	May 31, 2015	[1]	Feb. 28, 2015	[1]	Nov. 30, 2014	[1]	Aug. 31, 2014	[1],[2]	May 31, 2016	May 31, 2015	May 31, 2014
Diluted Earnings per Share from Continuing Operations
Income from continuing operations	$ 118,011	$ 117,279	$ 115,453	$ 106,198	$ 100,584		$ 100,331		$ 103,701		$ 105,905		$ 456,941	$ 410,521	$ 337,772
Less: income from continuing operations allocated to participating securities													7,405	3,900	3,082
Income from continuing operations available to common shareholders													$ 449,536	$ 406,621	$ 334,690
Basic weighted average common shares outstanding (shares)	106,136	107,843	108,301	110,597	113,666		116,178		117,115		116,659		108,221	115,900	120,377
Effect of dilutive securities - employee stock options (shares)													1,735	1,643	1,263
Diluted weighted average common shares outstanding (shares)													109,956	117,543	121,640
Diluted earnings per share:
Diluted earnings per share from continuing operations (dollars per share)	$ 1.08	$ 1.05	$ 1.03	$ 0.93	$ 0.86		$ 0.85		$ 0.86		$ 0.89		$ 4.09	$ 3.46	$ 2.75

[1] The figures for fiscal 2015 reflect the change in classification of Shred-it to discontinued operations within the Consolidated Statements of Income. See Note 16 entitled Discontinued Operations for additional information.

[2] During the fiscal 2015 first quarter, Cintas recognized a gain on the sale of stock in an equity method investment in the net amount of $13.6 million.