Earnings per Share - Summary of Buyback Activity by Program (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020
Equity, Class of Treasury Stock [Line Items]
Purchase Price	$ 1,525,873	$ 554,121	$ 464,518
Shares acquired for taxes due (in shares)	305	246	264
Shares acquired for taxes due, average price (in dollars per share)	$ 397.16	$ 302.52	$ 260.89
Shares acquired for taxes due	$ 121,224	$ 74,465	$ 68,837
Total repurchase of Cintas common stock	$ 1,525,873	$ 554,121	$ 464,518
Share Repurchase Programs
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	3,740	1,386	1,607
Average Price per Share (in dollars per share)	$ 375.53	$ 346.13	$ 246.19
Purchase Price	$ 1,404,649	$ 479,656	$ 395,681
Share Buyback Program October 2018
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	0	190	1,607
Average Price per Share (in dollars per share)	$ 0	$ 319.88	$ 246.19
Purchase Price	$ 0	$ 60,877	$ 395,681
Share Buyback Program October 2019
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	1,590	1,196	0
Average Price per Share (in dollars per share)	$ 365.41	$ 350.31	$ 0
Purchase Price	$ 581,220	$ 418,779	$ 0
Share Buyback Program July 27 2021
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	2,150	0	0
Average Price per Share (in dollars per share)	$ 383.01	$ 0	$ 0
Purchase Price	$ 823,429	$ 0	$ 0