Earnings Per Share (Schedule Of Computation Of Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Net earnings attributable to II-VI Incorporated	$ 13,287	$ 19,157	$ 31,866	$ 37,524
Weighted average shares	62,720,000	62,078,000	62,709,000	61,944,000
Basic earnings attributable to II-VI Incorporated per common share	$ 0.21	$ 0.31	$ 0.51	$ 0.61
Dilutive effect of common stock equivalents	1,474,000	1,702,000	1,457,000	1,546,000
Diluted weighted average common shares	64,194,000	63,780,000	64,166,000	63,490,000
Diluted earnings attributable to II-VI Incorporated per common share	$ 0.21	$ 0.30	$ 0.50	$ 0.59
Weighted average shares issuable upon the exercises of stock options excluded from the dilutive share calculation	147,000	234,000	209,000	364,000