Document and Entity Information	6 Months Ended
	Dec. 31, 2014	Feb. 03, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2014
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	IIVI
Entity Registrant Name	II-VI INC
Entity Central Index Key	0000820318
Current Fiscal Year End Date	--06-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		61,030,628