Supplemental Guarantor Information - Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net income	$ 884,981	$ 842,586	$ 480,708
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(21,572)	19,276	(10,252)
Change in fair value of interest rate lock agreements	(27,659)	0	31,136
Amortization of interest rate lock agreements	(1,179)	(933)	1,076
Other	(5,085)	1,029	(115)
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(55,495)	19,372	21,845
Comprehensive income	829,486	861,958	502,553
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income	(873,312)	(840,634)	(477,624)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	21,572	(19,276)	10,252
Change in fair value of interest rate lock agreements	27,659		(31,136)
Amortization of interest rate lock agreements	1,179	933	(1,076)
Other	5,085	(1,029)	115
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	55,495	(19,372)	(21,845)
Comprehensive income	(817,817)	(860,006)	(499,469)
Cintas Corporation | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net income	884,981	842,586	480,708
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(21,572)	19,276	(10,252)
Change in fair value of interest rate lock agreements	(27,659)		31,136
Amortization of interest rate lock agreements	(1,179)	(933)	1,076
Other	(5,085)	1,029	(115)
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(55,495)	19,372	21,845
Comprehensive income	829,486	861,958	502,553
Corp. 2 | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net income	234,085	342,851	152,916
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	0	0	0
Change in fair value of interest rate lock agreements	(27,659)		31,136
Amortization of interest rate lock agreements	(1,179)	(933)	1,076
Other	(4,489)	267	0
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(33,327)	(666)	32,212
Comprehensive income	200,758	342,185	185,128
Subsidiary Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net income	608,487	470,215	315,565
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	0	0	0
Change in fair value of interest rate lock agreements	0		0
Amortization of interest rate lock agreements	0	0	0
Other	(596)	762	(115)
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(596)	762	(115)
Comprehensive income	607,891	470,977	315,450
Non- Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net income	30,740	27,568	9,143
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(21,572)	19,276	(10,252)
Change in fair value of interest rate lock agreements	0		0
Amortization of interest rate lock agreements	0	0	0
Other	0	0	0
Other comprehensive (loss) income, net of tax (benefit) expense of ($9,635), $690 and $19,118, respectively	(21,572)	19,276	(10,252)
Comprehensive income	$ 9,168	$ 46,844	$ (1,109)