| Cover | Jan. 12, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 12, 2021 |
| Entity File Number | 001-31337 |
| Entity Registrant Name | CANTEL MEDICAL CORP. |
| Entity Central Index Key | 0000019446 |
| Entity Tax Identification Number | 22-1760285 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 150 Clove Road |
| Entity Address, City or Town | Little Falls |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 07424 |
| City Area Code | 973 |
| Local Phone Number | 890-7220 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | CMD |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
