Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands		12 Months Ended
		May. 31, 2015	May. 31, 2014	May. 31, 2013
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		$ 14,906	$ 15,855	$ 17,017
Charged to Costs and Expense	[1]	5,718	5,607	2,804
Charged to Other Accounts	[2]	(738)	(2,965)	202
Deductions	[3]	4,212	3,591	4,168
Balance at End of Year		15,674	14,906	15,855
Reserve for Obsolete Inventory
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year		30,673	29,487	29,376
Charged to Costs and Expense	[1]	3,278	3,147	4,041
Charged to Other Accounts	[2]	(364)	(144)	(2,223)
Deductions	[3]	2,880	1,817	1,707
Balance at End of Year		$ 30,707	$ 30,673	$ 29,487

[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 a change in the appropriate balance sheet reserve due to acquisitions and deconsolidations during the respective period.

[3] 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.