Document and Entity Information - shares	3 Months Ended
	Aug. 31, 2018	Sep. 30, 2018
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, 2018
Amendment Flag	false
Current Fiscal Year End Date	--05-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		106,895,291
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Entity Emerging Growth Company	false
Entity Small Business	false