Financial Information of Company's Operation by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Jun. 30, 2016
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	$ 244,987	$ 205,105	$ 698,329	$ 585,746
Operating income	29,039	19,390	79,866	62,899
Interest expense	(1,936)	(769)	(4,547)	(2,015)
Other income (expense), net	2,164	(1,257)	9,611	794
Income taxes	(6,837)	(2,426)	(22,303)	(10,535)
Net earnings	22,430	14,938	62,627	51,143
Depreciation and amortization	14,924	14,661	44,722	41,785
Segment assets	1,347,648		1,347,648		$ 1,211,981
Expenditures for property, plant & equipment	41,313	13,587	99,135	32,743
Investment	12,007		12,007		$ 11,354
Eliminations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Inter-segment revenues	(15,824)	(11,125)	(41,501)	(30,240)
II-VI Laser Solutions | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	83,648	73,778	244,421	215,552
Inter-segment revenues	9,661	5,962	24,361	15,342
Operating income	8,337	5,395	22,628	28,820
Depreciation and amortization	5,713	4,192	17,025	11,587
Segment assets	556,238		556,238
Expenditures for property, plant & equipment	23,299	7,156	59,161	16,511
II-VI Photonics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	109,099	80,603	305,824	226,762
Inter-segment revenues	3,450	3,363	10,049	9,160
Operating income	15,898	9,543	45,689	23,282
Depreciation and amortization	5,029	4,888	14,853	14,961
Segment assets	496,068		496,068
Expenditures for property, plant & equipment	8,727	4,160	21,224	10,783
II- VI Performance Products | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	52,240	50,724	148,084	143,432
Inter-segment revenues	2,713	1,800	7,091	5,738
Operating income	4,804	4,452	11,549	10,797
Depreciation and amortization	4,182	5,581	12,844	15,237
Segment assets	295,342		295,342
Expenditures for property, plant & equipment	9,287	$ 2,271	18,750	$ 5,449
Investment	$ 12,007		$ 12,007