Financial Information of Company's Operation by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	$ 231,822	$ 191,434	$ 453,342	$ 380,641
Operating income	27,136	21,781	50,827	43,509
Interest expense	(1,365)	(597)	(2,611)	(1,246)
Other income (expense), net	6,045	994	7,447	2,051
Income taxes	(7,913)	(3,187)	(15,466)	(8,109)
Net earnings	23,903	18,991	40,197	36,205
Depreciation and amortization	14,916	13,819	29,798	27,124
Segment assets	1,293,001		1,293,001		$ 1,211,981
Expenditures for property, plant & equipment	27,828	9,732	57,822	19,156
Investment	11,844		11,844		$ 11,354
Eliminations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Inter-segment revenues	(14,566)	(9,159)	(25,677)	(19,115)
II-VI Laser Solutions | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	81,483	70,191	160,773	141,774
Inter-segment revenues	8,760	4,850	14,700	9,380
Operating income	7,593	11,251	14,291	23,426
Depreciation and amortization	5,662	3,691	11,312	7,395
Segment assets	528,505		528,505
Expenditures for property, plant & equipment	15,737	3,475	35,862	9,355
II-VI Photonics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	100,906	74,264	196,725	146,159
Inter-segment revenues	3,161	2,766	6,599	5,797
Operating income	15,901	7,455	29,791	13,739
Depreciation and amortization	4,976	4,980	9,824	10,073
Segment assets	482,866		482,866
Expenditures for property, plant & equipment	5,900	4,471	12,497	6,623
II- VI Performance Products | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	49,433	46,979	95,844	92,708
Inter-segment revenues	2,645	1,543	4,378	3,938
Operating income	3,642	3,076	6,745	6,345
Depreciation and amortization	4,278	5,148	8,662	9,656
Segment assets	281,630		281,630
Expenditures for property, plant & equipment	6,191	$ 1,786	9,463	$ 3,178
Investment	$ 11,844		$ 11,844