Income Taxes	9 Months Ended
Feb. 28, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes In the normal course of business, Cintas provides for uncertain tax positions and the related interest, and adjusts its unrecognized tax benefits and accrued interest accordingly. During the three months ended February 28, 2013, unrecognized tax benefits increased by approximately $2.2 million and accrued interest increased by approximately $0.1 million. During the nine months ended February 28, 2013, unrecognized tax benefits decreased by approximately $29.9 million and accrued interest decreased by approximately $1.0 million. The decrease in unrecognized tax benefits for the nine months ended February 28, 2013, was due to a change in the IRS capitalization regulations adopted by Cintas in the second quarter of fiscal 2013 and resulted in a reclassification between long-term accrued liabilities and deferred tax liability. All U.S. federal income tax returns are closed to audit through fiscal 2010. Cintas is currently in advanced stages of various audits in certain foreign jurisdictions and certain domestic states. The years under audit cover fiscal years back to 2005. Based on the resolution of the various audits and changes in tax law, it is reasonably possible that the balance of unrecognized tax benefits could decrease by $1.3 million for the fiscal year ending May 31, 2013. On December 23, 2011, the U.S. Department of the Treasury and the Internal Revenue Service issued temporary regulations (Regulations Section 2011-14) that provide guidance on amounts paid to improve tangible property, and acquire or produce tangible property, as well as guidance regarding the disposition of property and the expensing of supplies and materials. The finalized regulations are effective for Cintas' fiscal year ending May 31, 2014. Due to the recently announced extension of effective date of the regulations and indications of changes to the de minimis and disposition rules, Cintas continues to review these regulations, but does not believe there will be a material impact on Cintas’ consolidated financial statements.

Income Taxes

9 Months Ended

Feb. 28, 2013

In the normal course of business, Cintas provides for uncertain tax positions and the related interest, and adjusts its unrecognized tax benefits and accrued interest accordingly. During the three months ended February 28, 2013, unrecognized tax benefits increased by approximately $2.2 million and accrued interest increased by approximately $0.1 million. During the nine months ended February 28, 2013, unrecognized tax benefits decreased by approximately $29.9 million and accrued interest decreased by approximately $1.0 million. The decrease in unrecognized tax benefits for the nine months ended February 28, 2013, was due to a change in the IRS capitalization regulations adopted by Cintas in the second quarter of fiscal 2013 and resulted in a reclassification between long-term accrued liabilities and deferred tax liability.

All U.S. federal income tax returns are closed to audit through fiscal 2010. Cintas is currently in advanced stages of various audits in certain foreign jurisdictions and certain domestic states. The years under audit cover fiscal years back to 2005. Based on the resolution of the various audits and changes in tax law, it is reasonably possible that the balance of unrecognized tax benefits could decrease by $1.3 million for the fiscal year ending May 31, 2013.

On December 23, 2011, the U.S. Department of the Treasury and the Internal Revenue Service issued temporary regulations (Regulations Section 2011-14) that provide guidance on amounts paid to improve tangible property, and acquire or produce tangible property, as well as guidance regarding the disposition of property and the expensing of supplies and materials. The finalized regulations are effective for Cintas' fiscal year ending May 31, 2014. Due to the recently announced extension of effective date of the regulations and indications of changes to the de minimis and disposition rules, Cintas continues to review these regulations, but does not believe there will be a material impact on Cintas’ consolidated financial statements.