Commitments and Contingencies	12 Months Ended
	Jun. 30, 2020
Guarantees [Abstract]
Commitments and Contingencies	Commitments and ContingenciesThe Company has purchase commitments for materials and supplies as part of the ordinary conduct of business. A portion of the commitments are long-term and are based on minimum purchase requirements. Certain short-term raw material purchase commitments have a variable price component which is based on market pricing at the time of purchase. Due to the proprietary nature of some of the Company’s materials and processes, certain contracts may contain liquidated damage provisions for early termination. The Company does not believe that a significant amount of liquidated damages are reasonably likely to be incurred under these commitments based upon historical experience and current expectations. The Company also has commitments relating to earnout arrangements on its acquisitions of $2.5 million. Total future commitments held by II-VI as of June 30, 2020, were $196.9 million in fiscal 2021, and $2.7 million thereafter.