Income Taxes	3 Months Ended
Aug. 31, 2017
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. As of August 31, 2017 and May 31, 2017, recorded unrecognized tax benefits were $13.7 million and $12.6 million, respectively, and are included in long-term accrued liabilities on the consolidated condensed balance sheet. The increase in the liability for the three months ended August 31, 2017 is primarily related to accrued interest on unrecognized tax benefits. All U.S. federal income tax returns are closed to audit through fiscal 2013. Cintas is currently in various audits in certain foreign jurisdictions and certain domestic states. The years under foreign and domestic state audits cover fiscal years back to 2013. Based on the resolution of the various audits and other potential regulatory developments, it is reasonably possible that the balance of unrecognized tax benefits would not change for the fiscal year ending May 31, 2018. The majority of Cintas' operations are in North America. Cintas is required to file federal income tax returns, as well as state income tax returns in a majority of the domestic states and also in certain Canadian provinces. At times, Cintas is subject to audits in these jurisdictions. The audits, by nature, are sometimes complex and can require several years to resolve. The final resolution of any such tax audit could result in either a reduction in Cintas' accruals or an increase in its income tax provision, either of which could have an impact on the consolidated condensed results of operations in any given period. Cintas’ effective tax rate for continuing operations was 26.5% and 28.2% for the three months ended August 31, 2017 and 2016, respectively. The effective tax rate for both periods was largely impacted by certain discrete items (primarily the tax accounting for stock-based compensation).

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. As of August 31, 2017 and May 31, 2017, recorded unrecognized tax benefits were $13.7 million and $12.6 million, respectively, and are included in long-term accrued liabilities on the consolidated condensed balance sheet. The increase in the liability for the three months ended August 31, 2017 is primarily related to accrued interest on unrecognized tax benefits.

All U.S. federal income tax returns are closed to audit through fiscal 2013. Cintas is currently in various audits in certain foreign jurisdictions and certain domestic states. The years under foreign and domestic state audits cover fiscal years back to 2013. Based on the resolution of the various audits and other potential regulatory developments, it is reasonably possible that the balance of unrecognized tax benefits would not change for the fiscal year ending May 31, 2018.

The majority of Cintas' operations are in North America. Cintas is required to file federal income tax returns, as well as state income tax returns in a majority of the domestic states and also in certain Canadian provinces. At times, Cintas is subject to audits in these jurisdictions. The audits, by nature, are sometimes complex and can require several years to resolve. The final resolution of any such tax audit could result in either a reduction in Cintas' accruals or an increase in its income tax provision, either of which could have an impact on the consolidated condensed results of operations in any given period.

Cintas’ effective tax rate for continuing operations was 26.5% and 28.2% for the three months ended August 31, 2017 and 2016, respectively. The effective tax rate for both periods was largely impacted by certain discrete items (primarily the tax accounting for stock-based compensation).