Earnings Per Share (Schedule Of Computation Of Earnings Per Share) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Share [Line Items]
Net Earnings Attributable to II-VI Incorporated	$ 14,446	$ 13,994	$ 13,287	$ 18,579	$ 22,039	$ 23,119	$ 19,157	$ 18,367	$ 60,306	$ 82,682	$ 38,577
Weighted average shares									62,823	62,211	60,304
Basic earnings attributable to II-VI Incorporated per common share	$ 0.23	$ 0.22	$ 0.21	$ 0.30	$ 0.35	$ 0.37	$ 0.31	$ 0.30	$ 0.96	$ 1.33	$ 0.64
Net earnings attributable to II-VI Incorporated	$ 14,446	$ 13,994	$ 13,287	$ 18,579	$ 22,039	$ 23,119	$ 19,157	$ 18,367	$ 60,306	$ 82,682	$ 38,577
Weighted average shares									62,823	62,211	60,304
Dilutive effect of Common Stock equivalents									1,562	1,401	1,200
Diluted weighted average common shares									64,385	63,612	61,504
Diluted earnings attributable to II-VI Incorporated per common share	$ 0.22	$ 0.22	$ 0.21	$ 0.29	$ 0.34	$ 0.36	$ 0.30	$ 0.29	$ 0.94	$ 1.30	$ 0.63