Operating Segment Information (Details) $ in Thousands		3 Months Ended												12 Months Ended
		May 31, 2016 USD ($)	Feb. 29, 2016 USD ($)	Nov. 30, 2015 USD ($)	Aug. 31, 2015 USD ($)	May 31, 2015 USD ($)		Feb. 28, 2015 USD ($)		Nov. 30, 2014 USD ($)		Aug. 31, 2014 USD ($)		May 31, 2016 USD ($) segment	May 31, 2015 USD ($)	May 31, 2014 USD ($)
Disclosures related to operating segments
Number of operating segments | segment														3
Revenue		$ 1,271,405	$ 1,216,083	$ 1,219,080	$ 1,198,890	$ 1,142,583		$ 1,108,847		$ 1,123,379		$ 1,102,077		$ 4,905,458	$ 4,476,886	$ 4,193,844
Gross margin		553,718	$ 524,608	$ 527,400	$ 524,144	486,660	[1]	$ 475,307	[1]	$ 481,424	[1]	$ 477,946	[1],[2]	2,129,870	1,921,337	1,749,759
Selling and administrative expenses														1,348,122	1,224,930	1,147,039
Gain on sale of stock of an equity method investment														0	21,739	0
Interest expense, net														63,626	64,822	65,593
Income before income taxes														718,122	653,324	537,127
Depreciation and amortization														165,279	152,595	147,289
Capital expenditures														275,385	217,720	145,580
Total assets		4,104,393				4,192,460								4,104,393	4,192,460	4,462,452
Operating Segments | Uniform Rental and Facility Services
Disclosures related to operating segments
Revenue														3,777,801	3,539,843	3,304,635
Gross margin														1,671,008	1,532,211	1,382,158
Selling and administrative expenses														998,069	926,176	860,311
Gain on sale of stock of an equity method investment															0
Interest expense, net														0	0	0
Income before income taxes														672,939	606,035	521,847
Depreciation and amortization														130,822	123,577	118,828
Capital expenditures														237,884	184,246	94,619
Total assets		3,114,159				2,845,326								3,114,159	2,845,326	2,840,809
Operating Segments | First Aid and Safety Services
Disclosures related to operating segments
Revenue														461,783	326,593	294,966
Gross margin														197,010	152,339	136,136
Selling and administrative expenses														147,503	107,226	96,246
Gain on sale of stock of an equity method investment															0
Interest expense, net														0	0	0
Income before income taxes														49,507	45,113	39,890
Depreciation and amortization														16,021	9,774	8,283
Capital expenditures														22,364	13,589	9,195
Total assets		421,789				255,202								421,789	255,202	257,603
Operating Segments | All Other
Disclosures related to operating segments
Revenue														665,874	610,450	594,243
Gross margin														261,852	236,787	231,465
Selling and administrative expenses														202,550	191,528	190,482
Gain on sale of stock of an equity method investment															0
Interest expense, net														0	0	0
Income before income taxes														59,302	45,259	40,983
Depreciation and amortization														18,436	19,244	20,178
Capital expenditures														15,137	18,983	7,370
Total assets		358,683				345,201								358,683	345,201	340,650
Corporate
Disclosures related to operating segments
Revenue														0	0	0
Gross margin														0	0	0
Selling and administrative expenses														0	0	0
Gain on sale of stock of an equity method investment															21,739
Interest expense, net														63,626	64,822	65,593
Income before income taxes														(63,626)	(43,083)	(65,593)
Depreciation and amortization														0	0	0
Capital expenditures														0	902	34,396
Total assets	[3]	$ 209,762				$ 746,731								$ 209,762	$ 746,731	$ 1,023,390

[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.

[3] Corporate assets include cash and marketable securities in all periods. Corporate assets as of May 31, 2015 include Shred-it and real estate assets of Storage that were not included in the sale transactions. Corporate assets as of May 31, 2014 include Shred-it and the assets of Storage.