Earnings per Share - Computation of Basic Earnings Per Share (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
Basic 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
Basic earnings per share:
Basic earnings (loss) per share, continuing operations (dollars per share)	$ 1.09	$ 1.07	$ 1.05	$ 0.94	$ 0.87		$ 0.86		$ 0.88		$ 0.90		$ 4.15	$ 3.51	$ 2.78

[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.