Cover Page - USD ($)	12 Months Ended
	Jul. 31, 2020	Aug. 31, 2020	Jan. 31, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Jul. 31, 2020
Document Transition Report	false
Entity File Number	001-31337
Entity Registrant Name	Cantel Medical Corp.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-1760285
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
Title of 12(b) Security	Common Stock, $0.10 par value
Trading Symbol	CMD
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 2,770,207,632
Entity Common Stock, Shares Outstanding		42,162,536
Documents Incorporated by Reference	Documents incorporated by reference: Portions of the definitive proxy statement to be filed pursuant to Regulation 14A promulgated under the Securities Exchange Act of 1934 in connection with the 2020 Annual Meeting of Stockholders of Registrant are hereby incorporated by reference into Part III of this Form 10-K and certain documents are incorporated by reference into Part IV.
Entity Central Index Key	0000019446
Amendment Flag	false
Current Fiscal Year End Date	--07-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY