Financial Information of Company's Operation by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	$ 221,520	$ 189,207
Operating income	23,691	21,728
Interest expense	(1,246)	(649)
Other income, net	1,402	1,057
Income taxes	(7,553)	(4,922)
Net earnings	16,294	17,214
Depreciation and amortization	14,882	13,305
Segment assets	1,228,487		$ 1,211,981
Expenditures for property, plant & equipment	29,994	9,424
Investment	11,684		11,354
Goodwill	233,604		233,755
Eliminations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Inter-segment revenues	(11,111)	(9,956)
II-VI Laser Solutions
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	84,113		84,105
II-VI Laser Solutions | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	79,290	71,583
Inter-segment revenues	5,940	4,530
Operating income	6,698	12,175
Depreciation and amortization	5,650	3,704
Segment assets	476,617
Expenditures for property, plant & equipment	20,125	5,880
Goodwill	84,113
II-VI Photonics
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	96,601		96,760
II-VI Photonics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	95,819	71,895
Inter-segment revenues	3,438	3,031
Operating income	13,890	6,284
Depreciation and amortization	4,848	5,093
Segment assets	473,569
Expenditures for property, plant & equipment	6,597	2,152
Goodwill	96,601
II- VI Performance Products
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	52,890		$ 52,890
II- VI Performance Products | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	46,411	45,729
Inter-segment revenues	1,733	2,395
Operating income	3,103	3,269
Depreciation and amortization	4,384	4,508
Segment assets	278,301
Expenditures for property, plant & equipment	3,272	$ 1,392
Investment	11,684
Goodwill	$ 52,890