Supplemental Guarantor Information - Condensed Consolidating Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Condensed Consolidating Financial Statements
Net income	$ 480,708	$ 693,520	$ 430,618
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(10,252)	(11,933)	(38,538)
Cumulative translation adjustment on Shred-it	0	6,472	0
Change in fair value of cash flow hedges	31,136	(12,156)	37
Amortization of interest rate lock agreements	1,076	1,952	1,952
Other	(115)	(738)	(350)
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	21,845	(16,403)	(36,899)
Comprehensive income (loss)	502,553	677,117	393,719
Eliminations
Condensed Consolidating Financial Statements
Net income	(477,624)	(700,704)	(433,022)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	10,252	0	0
Cumulative translation adjustment on Shred-it		0
Change in fair value of cash flow hedges	(31,136)	0	0
Amortization of interest rate lock agreements	(1,076)	0	0
Other	115	0	0
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	(21,845)	0	0
Comprehensive income (loss)	(499,469)	(700,704)	(433,022)
Cintas Corporation | Reportable Legal Entities
Condensed Consolidating Financial Statements
Net income	480,708	693,520	430,618
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(10,252)	0	0
Cumulative translation adjustment on Shred-it		0
Change in fair value of cash flow hedges	31,136	0	0
Amortization of interest rate lock agreements	1,076	0	0
Other	(115)	0	0
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	21,845	0	0
Comprehensive income (loss)	502,553	693,520	430,618
Corp. 2 | Reportable Legal Entities
Condensed Consolidating Financial Statements
Net income	152,916	400,191	149,937
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	0	0	0
Cumulative translation adjustment on Shred-it		5,875
Change in fair value of cash flow hedges	31,136	(12,156)	0
Amortization of interest rate lock agreements	1,076	1,952	1,952
Other	0	0	0
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	32,212	(4,329)	1,952
Comprehensive income (loss)	185,128	395,862	151,889
Subsidiary Guarantors | Reportable Legal Entities
Condensed Consolidating Financial Statements
Net income	315,565	296,608	266,084
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	0	0	0
Cumulative translation adjustment on Shred-it		0
Change in fair value of cash flow hedges	0	0	0
Amortization of interest rate lock agreements	0	0	0
Other	(115)	(730)	(361)
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	(115)	(730)	(361)
Comprehensive income (loss)	315,450	295,878	265,723
Non- Guarantors | Reportable Legal Entities
Condensed Consolidating Financial Statements
Net income	9,143	3,905	17,001
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(10,252)	(11,933)	(38,538)
Cumulative translation adjustment on Shred-it		597
Change in fair value of cash flow hedges	0	0	37
Amortization of interest rate lock agreements	0	0	0
Other	0	(8)	11
Other comprehensive income (loss), net of tax expense (benefit) of $19,118, ($9,813), and $1,043, respectively	(10,252)	(11,344)	(38,490)
Comprehensive income (loss)	$ (1,109)	$ (7,439)	$ (21,489)