Revenue from Contracts with Customers - Summary of Disaggregated Revenue by Market and Product (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenue	$ 362,728	$ 342,496	$ 342,839	$ 314,433	$ 321,075	$ 294,746	$ 281,470	$ 261,503	$ 1,362,496	$ 1,158,794	$ 972,046
II-VI Laser Solutions
Disaggregation Of Revenue [Line Items]
Revenue									396,573
II-VI Photonics
Disaggregation Of Revenue [Line Items]
Revenue									638,889
II-VI Performance Products
Disaggregation Of Revenue [Line Items]
Revenue									327,034
Commercial | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									1,194,509
Commercial | Services
Disaggregation Of Revenue [Line Items]
Revenue									21,646
Commercial | II-VI Laser Solutions | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									382,066
Commercial | II-VI Laser Solutions | Services
Disaggregation Of Revenue [Line Items]
Revenue									3,738
Commercial | II-VI Photonics | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									631,407
Commercial | II-VI Photonics | Services
Disaggregation Of Revenue [Line Items]
Revenue									7,482
Commercial | II-VI Performance Products | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									181,036
Commercial | II-VI Performance Products | Services
Disaggregation Of Revenue [Line Items]
Revenue									10,426
U.S. Government | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									130,313
U.S. Government | Services
Disaggregation Of Revenue [Line Items]
Revenue									16,028
U.S. Government | II-VI Laser Solutions | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									10,751
U.S. Government | II-VI Laser Solutions | Services
Disaggregation Of Revenue [Line Items]
Revenue									18
U.S. Government | II-VI Performance Products | Direct Ship Parts
Disaggregation Of Revenue [Line Items]
Revenue									119,562
U.S. Government | II-VI Performance Products | Services
Disaggregation Of Revenue [Line Items]
Revenue									$ 16,010