Computation of Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Line Items]
Earnings from continuing operations attributable to II-VI Incorporated									$ 38,316	$ 57,602	$ 69,749
Earnings (loss) from discontinued operation			131	2	(4,226)	(166)	(608)	(1,789)	133	(6,789)	(9,443)
Net Earnings Attributable to II-VI Incorporated	$ 12,655	$ 8,531	$ 7,569	$ 9,694	$ 10,026	$ 15,869	$ 12,200	$ 12,718	$ 38,449	$ 50,813	$ 60,306
Weighted average shares									62,248	62,411	62,823
Basic earnings (loss) attributable to II-VI Incorporated per common share:
Continuing operations	$ 0.21	$ 0.14	$ 0.12	$ 0.16	$ 0.23	$ 0.26	$ 0.20	$ 0.23	$ 0.62	$ 0.92	$ 1.10
Discontinued operation				$ 0.00	$ (0.07)	$ 0.00	$ (0.01)	$ (0.03)		$ (0.11)	$ (0.15)
Consolidated	$ 0.21	$ 0.14	$ 0.12	$ 0.16	$ 0.16	$ 0.26	$ 0.19	$ 0.20	$ 0.62	$ 0.81	$ 0.96
Diluted effect of common stock equivalents									1,438	1,473	1,562
Diluted weighted average common shares									63,686	63,884	64,385
Diluted earnings (loss) attributable to II-VI Incorporated per common share:
Continuing operations	$ 0.20	$ 0.13	$ 0.12	$ 0.15	$ 0.22	$ 0.25	$ 0.20	$ 0.23	$ 0.60	$ 0.90	$ 1.08
Discontinued operation				$ 0.00	$ (0.07)	$ 0.00	$ (0.01)	$ (0.03)		$ (0.11)	$ (0.15)
Consolidated	$ 0.20	$ 0.13	$ 0.12	$ 0.15	$ 0.16	$ 0.25	$ 0.19	$ 0.20	$ 0.60	$ 0.80	$ 0.94