Operating Segment Information (Details) $ in Thousands		3 Months Ended																	12 Months Ended
		May. 31, 2015 USD ($)		Feb. 28, 2015 USD ($)	[1],[2],[3]	Nov. 30, 2014 USD ($)	[1],[2],[3]	Aug. 31, 2014 USD ($)	[1],[2],[3]	Aug. 30, 2014 segment	May. 31, 2014 USD ($)		Feb. 28, 2014 USD ($)	[1],[3],[4]	Nov. 30, 2013 USD ($)	[1],[3],[4]	Aug. 31, 2013 USD ($)	[1],[3],[4]	May. 31, 2015 USD ($) segment		May. 31, 2014 USD ($)	May. 31, 2013 USD ($)
Disclosures related to operating segments
Number of operating segments | segment										4									3
Revenue		$ 1,142,583	[1],[2],[3]	$ 1,108,847		$ 1,123,379		$ 1,102,077			$ 1,134,415	[1],[3],[4]	$ 1,110,973		$ 1,123,931		$ 1,100,246		$ 4,476,886		$ 4,469,565	$ 4,245,964
Gross margin		486,660	[1],[2],[3]	$ 475,307		$ 481,424		$ 477,946			480,847	[1],[3],[4]	$ 469,634		$ 467,079		$ 456,095		1,921,337		1,873,654	1,753,309
Selling and admin. expenses																			1,224,930		1,264,836	1,187,331
Gain on deconsolidation of Shredding																			4,952		61,817
Gain on sale of stock of an equity method investment																			21,739		0	0
Interest expense, net																			64,822		65,593	65,303
Income before income taxes																			658,276		605,042	500,675
Depreciation and amortization																			152,595		181,045	179,909
Capital expenditures																			217,720		145,580	196,486
Total assets		4,192,460									4,462,452								4,192,460		4,462,452	4,345,632
Operating Segments | Rental Uniforms & Ancillary Products
Disclosures related to operating segments
Revenue																			3,454,956		3,223,930	3,044,587
Gross margin																			1,541,490		1,394,503	1,288,290
Selling and admin. expenses																			948,455		887,444	835,249
Gain on deconsolidation of Shredding																			0		0
Gain on sale of stock of an equity method investment																			0
Interest expense, net																			0		0	0
Income before income taxes																			593,035		507,059	453,041
Depreciation and amortization																			121,743		117,869	116,867
Capital expenditures																			183,459		94,190	140,327
Total assets		2,856,716									2,875,014								2,856,716		2,875,014	2,830,941
Operating Segments | Uniform Direct Sales
Disclosures related to operating segments
Revenue																			453,653		455,485	461,328
Gross margin																			129,446		130,018	134,985
Selling and admin. expenses																			85,317		83,309	81,739
Gain on deconsolidation of Shredding																			0		0
Gain on sale of stock of an equity method investment																			0
Interest expense, net																			0		0	0
Income before income taxes																			44,129		46,709	53,246
Depreciation and amortization																			8,391		8,307	8,049
Capital expenditures																			9,495		2,482	6,908
Total assets		123,044									142,033								123,044		142,033	152,551
Operating Segments | First Aid, Safety & Fire Protection
Disclosures related to operating segments
Revenue																			568,277		514,429	460,592
Gross margin																			250,401		225,238	199,314
Selling and admin. expenses																			191,158		176,286	156,232
Gain on deconsolidation of Shredding																			0		0
Gain on sale of stock of an equity method investment																			0
Interest expense, net																			0		0	0
Income before income taxes																			59,243		48,952	43,082
Depreciation and amortization																			22,461		21,113	20,832
Capital expenditures																			23,864		14,512	11,809
Total assets		436,651									422,015								436,651		422,015	398,614
Corporate
Disclosures related to operating segments
Revenue	[5]																		0		275,721	279,457
Gross margin	[5]																		0		123,895	130,720
Selling and admin. expenses	[5]																		0		117,797	114,111
Gain on deconsolidation of Shredding	[5]																		4,952		61,817
Gain on sale of stock of an equity method investment	[5]																		21,739
Interest expense, net																			64,822	[5]	65,593	65,303	[5]
Income before income taxes	[5]																		(38,131)		2,322	(48,694)
Depreciation and amortization	[5]																		0		33,756	34,161
Capital expenditures	[5]																		902		34,396	37,442
Total assets	[5]	$ 776,049									1,023,390								$ 776,049		1,023,390	963,526
Corporate | Cintas Shredding
Disclosures related to operating segments
Revenue																					275,700	279,500
Gross margin																					38,500	16,600
Total assets											$ 344,300										$ 344,300	$ 456,300

[1] As a result of the Shredding Transaction, Cintas no longer includes Shredding results in its reported revenue, gross margin and operating income. After April 30, 2014, Cintas recognized its share of the Shred-it Partnership income, net of tax, in net income from continuing operations and diluted earnings per share ("EPS") from continuing operations. As a result of its investment in the Shred-it Partnership, Cintas recognized a net loss of $5.5 million and a net gain of $1.2 million during the years end May 31, 2015 and 2014, respectively.

[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. In the fiscal 2015 first quarter, Cintas also recorded an net gain of $4.1 million, related to the Shredding Transaction completed in fiscal 2014 as a result of receiving certain additional proceeds. Finally, in the fourth quarter of fiscal 2015, Cintas recorded a net loss of $1.0 million related to the Shredding Transaction completed in fiscal 2014 due to the settlement of an outstanding Shredding-related legal claim.

[3] The figures for both fiscal 2015 and 2014 reflect the change in classification of Storage to discontinued operations within the Consolidated Statements of Income. See Note 17 entitled Discontinued Operations for additional information.

[4] In accordance with GAAP, the fiscal 2014 Shredding revenue, gross margin, operating income, net income and EPS must continue to be included in the reported fiscal 2014 results because of Cintas' continuing ownership in the Shred-it Partnership. In addition, the fiscal 2014 results also included the following related to the Shredding Transaction: a $106.4 million gain on deconsolidation of Shredding, an asset impairment charge of $16.1 million and transaction costs of $28.5 million. All of these impacts were recorded in the fourth quarter except for $2.2 million of transaction costs that were recorded in the third quarter. Please see Note 9 entitled Acquisitions and Deconsolidations for additional information on the transaction.

[5] Corporate assets as of May 31, 2015 include the investment in the Shred-it Partnership. Corporate assets also include the real estate assets of Storage that were not included in the sale transactions. Corporate results and assets as of and for the fiscal year ended 2014 include the revenue ($275.7 million), loss before income taxes ($38.5 million) and assets ($344.3 million) of Shredding. Corporate results and assets as of and for the fiscal year ended 2013 include the revenue ($279.5 million), income before income taxes ($16.6 million) and assets ($456.3 million) of Shredding. Corporate assets as of May 31, 2014 and 2013 include the assets of Storage.