Segment And Geographic Reporting (Schedule Of Financial Information Of Company's Operations By Segment) (Detail) (USD $) In Thousands, 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
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	$ 136,910	$ 132,590	$ 126,757	$ 138,373	$ 131,783	$ 129,997	$ 120,887	$ 120,134	$ 534,630	$ 502,801	$ 345,091
Segment earnings									71,939	98,775	51,681
Interest expense	28	48	77	59	14	34	25	30	212	103	87
Other expense, net	1,721	2,311	1,506	1,630	57	1,431	(460)	2,062	7,168	3,090	(277)
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
Depreciation and amortization									34,693	28,446	21,039
Segment assets	706,486				647,202				706,486	647,202
Expenditures for property, plant and equipment									42,840	40,859	13,837
Equity investment	10,661				15,458				10,661	15,458
Goodwill	80,748				64,262				80,748	64,262	56,088
Infrared Optics
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues									201,611	180,827	135,063
Inter-segment revenues									3,174	3,282	2,021
Segment earnings									51,095	46,187	24,582
Depreciation and amortization									8,480	8,268	8,337
Segment assets	220,550				264,052				220,550	264,052
Expenditures for property, plant and equipment									8,072	9,065	1,817
Goodwill	9,612				10,038				9,612	10,038	9,525
Near-Infrared Optics
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues									161,078	159,803	88,499
Inter-segment revenues									1,053	299	303
Segment earnings									10,511	24,113	12,304
Depreciation and amortization									17,993	13,710	7,684
Segment assets	289,991				205,897				289,991	205,897
Expenditures for property, plant and equipment									15,759	16,795	4,115
Goodwill	50,423				33,511				50,423	33,511	32,335
Military & Materials
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues									97,385	83,426	65,674
Inter-segment revenues									5,498	6,520	2,137
Segment earnings									1,891	15,255	9,307
Depreciation and amortization									3,937	3,079	2,007
Segment assets	91,113				84,371				91,113	84,371
Expenditures for property, plant and equipment									8,516	5,414	4,706
Goodwill	10,399				10,399				10,399	10,399	3,914
Advanced Products Group
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues									74,556	78,745	55,855
Inter-segment revenues									4,295	5,015	4,209
Segment earnings									8,442	13,220	5,488
Depreciation and amortization									4,283	3,389	3,011
Segment assets	104,832				92,882				104,832	92,882
Expenditures for property, plant and equipment									10,493	9,585	3,199
Equity investment	10,661				15,458				10,661	15,458
Goodwill	10,314				10,314				10,314	10,314	10,314
Eliminations
Schedule Of Identifiable Assets By Segment [Line Items]
Inter-segment revenues									$ (14,020)	$ (15,116)	$ (8,670)