Computation of Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share [Line Items]
Net earnings attributable to II-VI Incorporated	$ 15,869	$ 13,994	$ 40,787	$ 45,860
Weighted average shares	62,130	62,855	62,482	62,752
Basic earnings attributable to II-VI Incorporated per common share	$ 0.26	$ 0.22	$ 0.65	$ 0.73
Dilutive effect of common stock equivalents	1,594	1,773	1,483	1,562
Diluted weighted average common shares	63,724	64,628	63,965	64,314
Diluted earnings attributable to II-VI Incorporated per common share	$ 0.25	$ 0.22	$ 0.64	$ 0.71