Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands		12 Months Ended
		May 31, 2017	May 31, 2016	May 31, 2015
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		$ 19,103	$ 15,497	$ 14,262
Additions	[1]	6,446	8,274	5,289
Deductions	[2]	5,024	4,668	4,054
Balance at End of Year		20,525	19,103	15,497
Reserve for Obsolete Inventory
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		32,716	30,531	30,459
Additions	[1]	10,049	5,195	2,952
Deductions	[2]	4,460	3,010	2,880
Balance at End of Year		$ 38,305	$ 32,716	$ 30,531

[1] Represents amounts charged to expense to increase reserve for estimated future bad debts or to increase reserve for obsolete inventory. Amounts related to inventory are computed by performing a thorough analysis of future marketability by specific inventory item as well as an estimate based on Cintas' historical rates of obsolescence. (2)Represents reductions in the balance sheet reserve due to the actual write-off of non-collectible accounts receivable or the physical disposal of obsolete inventory items. These amounts do not impact Cintas' consolidated income statement.

[2] Represents reductions in the balance sheet reserve due to the actual write-off of non-collectible accounts receivable or the physical disposal of obsolete inventory items. These amounts do not impact Cintas' consolidated income statement.