Basis of Presentation (Policies)	6 Months Ended
Basis of Presentation (Policies)	Nov. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The consolidated condensed financial statements of Cintas Corporation (Cintas, the Company, we, us or our) included herein have been prepared by Cintas, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with United States generally accepted accounting principles (U.S. GAAP) have been condensed or omitted pursuant to such rules and regulations. While we believe that the disclosures are adequately presented, we suggest that these consolidated condensed financial statements be read in conjunction with the consolidated financial statements and notes included in our Annual Report on Form 10-K for the fiscal year ended May 31, 2020. A summary of our significant accounting policies is presented beginning on page 40 of that report. There have been no material changes in the accounting policies followed by Cintas during the current fiscal year other than the adoption of new accounting pronouncements discussed below. Interim results are subject to variations and are not necessarily indicative of the results of operations for a full fiscal year. In the opinion of management, adjustments (which include only normal recurring adjustments) necessary for a fair statement of the consolidated results of the interim periods shown have been made.
Inventory	Inventories, net are valued at the lower of cost (first-in, first-out) or net realizable value.Inventories are recorded net of reserves for obsolete inventory of $52.3 million and $45.5 million at November 30, 2020 and May 31, 2020, respectively. The inventory obsolescence reserve is determined by specific identification, as well as an estimate based on Cintas' historical rates of obsolescence. Once a specific inventory item is written down to the lower of cost or net realizable value, a new cost basis has been established, and that inventory item cannot subsequently be marked up.
New Accounting Pronouncements	Effective June 1, 2020, the Company adopted Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In connection with recognizing credit losses on accounts receivable and other financial instruments, Cintas now uses a forward-looking expected loss model rather than the incurred loss model. Adoption of ASU 2016-13 requires using a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the effective date to align existing credit loss methodology with the new standard. The adoption of ASU 2016-13 did not have a material impact on the Company's consolidated condensed financial statements. No other new accounting pronouncement recently issued or newly effective had or is expected to have a material impact on Cintas' consolidated condensed financial statements.

Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.