Earnings per Share - Schedule of Buyback Activity by Program (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	May 31, 2025	May 31, 2024	May 31, 2023
Equity, Class of Treasury Stock [Line Items]
Purchase Price	$ 934,800	$ 700,033	$ 398,865
Shares acquired for taxes due (in shares)	1,297	1,325	1,719
Shares acquired for taxes due, average price (in dollars per share)	$ 196.87	$ 139.34	$ 105.05
Shares acquired for taxes due	$ 255,471	$ 184,645	$ 180,577
Total repurchase of Cintas common stock	$ 934,800	$ 700,033	$ 398,865
Share Repurchase Programs
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	3,794	3,764	2,201
Average Price per Share (in dollars per share)	$ 179.07	$ 136.92	$ 99.17
Purchase Price	$ 679,329	$ 515,388	$ 218,288
Share Buyback Program July 27 2021
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	0	3,425	2,201
Average Price per Share (in dollars per share)	$ 0	$ 133.80	$ 99.17
Purchase Price	$ 0	$ 458,284	$ 218,288
Share Buyback Program July 26 2022
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	3,794	339	0
Average Price per Share (in dollars per share)	$ 179.07	$ 168.44	$ 0
Purchase Price	$ 679,329	$ 57,104	$ 0
Share Buyback Program July 23 2024
Equity, Class of Treasury Stock [Line Items]
Shares (in shares)	0	0	0
Average Price per Share (in dollars per share)	$ 0	$ 0	$ 0
Purchase Price	$ 0	$ 0	$ 0