Financial Information of Company's Operation by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	$ 196,683	$ 182,709	$ 176,736	$ 185,833	$ 187,921	$ 173,555	$ 171,765	$ 150,020	$ 741,961	$ 683,261	$ 551,075
Operating income (loss)									76,799	46,486	71,491
Interest expense	(777)	(844)	(1,038)	(1,204)	(1,415)	(1,412)	(1,169)	(483)	(3,863)	(4,479)	(1,160)
Other income, net	97	(1,534)	9,295	(1,682)	868	1,694	1,125	(53)	6,176	3,634	7,155
Income taxes	(5,464)	(773)	(2,692)	(4,208)	(1,502)	(494)	(2,086)	(3,243)	(13,137)	(7,325)	(18,766)
Earnings (loss) from discontinued operation							131	2		133	(6,789)
Net earnings	17,069	$ 14,508	$ 22,096	$ 12,302	12,655	$ 8,531	$ 7,569	$ 9,694	65,975	38,449	51,931
Depreciation and amortization									53,083	53,098	40,792
Expenditures for property, plant and equipment									52,313	29,220	25,205
Segment assets	1,058,164				1,071,926				1,058,164	1,071,926
Equity investment	11,914				11,589				11,914	11,589
Goodwill	195,894				196,145				195,894	196,145	123,352
Eliminations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Inter-segment revenues									(43,556)	(31,358)	(19,079)
II-VI Laser Solutions
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	43,578				44,041				43,578	44,041	13,233
II-VI Laser Solutions | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									287,881	254,342	217,604
Inter-segment revenues									21,021	9,825	5,671
Operating income (loss)									55,039	24,457	53,963
Depreciation and amortization									14,127	15,018	8,554
Expenditures for property, plant and equipment									27,349	11,797	6,536
Segment assets	330,308				312,281				330,308	312,281
Goodwill	43,578				44,041				43,578	44,041
II-VI Photonics
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	99,426				99,214				99,426	99,214	56,713
II-VI Photonics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									260,825	216,493	141,319
Inter-segment revenues									13,210	9,533	3,950
Operating income (loss)									7,208	(113)	15,037
Depreciation and amortization									21,073	20,123	17,181
Expenditures for property, plant and equipment									11,324	8,359	8,849
Segment assets	450,763				468,055				450,763	468,055
Goodwill	99,426				99,214				99,426	99,214
II- VI Performance Products
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	52,890				52,890				52,890	52,890	53,406
II- VI Performance Products | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									193,255	212,426	192,152
Inter-segment revenues									9,325	12,000	9,458
Operating income (loss)									14,552	22,142	2,491
Depreciation and amortization									17,883	17,957	15,057
Expenditures for property, plant and equipment									13,640	9,064	$ 9,820
Segment assets	277,093				291,590				277,093	291,590
Equity investment	11,914				11,589				11,914	11,589
Goodwill	$ 52,890				$ 52,890				$ 52,890	$ 52,890