v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Feb. 28, 2018
Apr. 02, 2018
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Feb. 28, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Trading Symbol RPM  
Entity Registrant Name RPM INTERNATIONAL INC/DE/  
Entity Central Index Key 0000110621  
Current Fiscal Year End Date --05-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   133,729,592