Quarterly Financial Data (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
Quarterly Financial Data [Line Items]
Net revenues	$ 136,910	$ 132,590	$ 126,757	$ 138,373	$ 131,783	$ 129,997	$ 120,887	$ 120,134	$ 534,630	$ 502,801	$ 345,091
Cost of goods sold, including contract activity	88,648	86,589	83,289	83,363	77,004	77,149	70,851	70,898
Internal research and development	5,533	5,698	5,016	5,163	4,984	3,892	3,357	3,846	21,410	16,079	11,806
Selling, general and administrative	25,037	23,329	24,214	26,812	24,039	23,286	21,991	22,729	99,392	92,045	71,112
Interest expense	28	48	77	59	14	34	25	30	212	103	87
Other expense (income) - net	(1,721)	(2,311)	(1,506)	(1,630)	(57)	(1,431)	460	(2,062)	(7,168)	(3,090)	277
Earnings Before Income Taxes	19,385	19,237	15,667	24,606	25,799	27,067	24,203	24,693	78,895	101,762	51,317
Income taxes	4,614	4,967	2,147	5,892	3,633	3,871	4,948	6,292	17,620	18,744	12,582
Net earnings	14,771	14,270	13,520	18,714	22,166	23,196	19,255	18,401	61,275	83,018	38,735
Net Earnings Attributable to Noncontrolling Interests	325	276	233	135	127	77	98	34	969	336	158
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
Net Earnings Attributable to II-VI Incorporated: Basic Earnings Per 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: Diluted Earnings Per Share:	$ 0.22	$ 0.22	$ 0.21	$ 0.29	$ 0.34	$ 0.36	$ 0.30	$ 0.29	$ 0.94	$ 1.30	$ 0.63