Document and Entity Information - shares	3 Months Ended
	Aug. 31, 2017	Sep. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	CINTAS CORP
Entity Central Index Key	0000723254
Document Type	10-Q
Document Period End Date	Aug. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--05-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		106,304,385
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1