Cover - shares	3 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-39375
Entity Registrant Name	II-VI INCORPORATED
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	25-1214948
Entity Address, Address Line One	375 Saxonburg Boulevard
Entity Address, Postal Zip Code	16056
Entity Address, City or Town	Saxonburg,
Entity Address, State or Province	PA
City Area Code	724
Local Phone Number	352-4455
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		106,139,773
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--06-30
Amendment Flag	false
Entity Central Index Key	0000820318
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	IIVI
Security Exchange Name	NASDAQ
Series A Mandatory Convertible Preferred Stock
Entity Information [Line Items]
Title of 12(b) Security	Series A Mandatory Convertible Preferred Stock, no par value
Trading Symbol	IIVIP
Security Exchange Name	NASDAQ