Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	May 31, 2023	Jun. 30, 2023	Nov. 30, 2022
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	May 31, 2023
Entity File Number	1-6263
Entity Registrant Name	AAR CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-2334820
Entity Address, Address Line One	One AAR Place
Entity Address, Address Line Two	1100 N. Wood Dale Road
Entity Address, City or Town	Wood Dale
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60191
City Area Code	630
Local Phone Number	227-2000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,524
Entity Common Stock, Shares Outstanding		34,934,957
Entity Central Index Key	0000001750
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--05-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2023
Amendment Flag	false
ICFR Auditor Attestation Flag	true
Auditor Name	KPMG LLP
Auditor Firm ID	185
Auditor Location	Chicago, Illinois
Common Stock | NEW YORK STOCK EXCHANGE, INC.
Document and Entity Information
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	AIR
Security Exchange Name	NYSE
Common Stock | CHICAGO STOCK EXCHANGE, INC
Document and Entity Information
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	AIR
Security Exchange Name	CHX