| Document and Entity Information | Oct. 06, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0000110621 |
| Document Type | 8-K |
| Document Period End Date | Oct. 6, 2021 |
| Entity Registrant Name | RPM INTERNATIONAL INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-14187 |
| Entity Tax Identification Number | 02-0642224 |
| Entity Address, Address Line One | 2628 Pearl Road |
| Entity Address, Address Line Two | P.O. Box 777 |
| Entity Address, City or Town | Medina |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 44258 |
| City Area Code | (330) |
| Local Phone Number | 273-5090 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 |
| Trading Symbol | RPM |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
