Segment Reporting (Schedule Of Financial Information Of Company's Operations By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2011
Segment Reporting Information [Line Items]
Revenues	$ 126,757	$ 120,887	$ 265,130	$ 241,021
Segment earnings (loss)	14,238	24,688	37,273	47,349
Interest expense	(77)	(25)	(136)	(55)
Other income (expense), net	1,506	(460)	3,136	1,602
Income taxes	(2,147)	(4,948)	(8,039)	(11,240)
Net earnings	13,520	19,255	32,234	37,656
Depreciation and amortization	8,522	6,845	16,832	13,679
Segment assets	678,497	566,835	678,497	566,835	647,202
Expenditures for property, plant and equipment	10,356	9,387	23,068	14,668
Equity investments	15,938	15,436	15,938	15,436
Goodwill	84,785	66,135	84,785	66,135	64,262
Infrared Optics [Member]
Segment Reporting Information [Line Items]
Revenues	46,762	40,642	97,558	81,868
Inter-segment revenues	1,046	857	1,704	1,371
Segment earnings (loss)	11,470	9,420	23,827	18,068
Interest expense
Other income (expense), net
Income taxes
Net earnings
Depreciation and amortization	2,139	2,065	4,334	4,096
Segment assets	206,543	213,072	206,543	213,072
Expenditures for property, plant and equipment	2,127	1,799	3,827	2,585
Goodwill	9,696	9,800	9,696	9,800	10,038
Near-Infrared Optics [Member]
Segment Reporting Information [Line Items]
Revenues	39,468	41,418	77,578	78,363
Inter-segment revenues	190	72	412	122
Segment earnings (loss)	1,684	8,068	3,392	14,949
Depreciation and amortization	4,349	3,346	8,564	6,758
Segment assets	277,875	195,902	277,875	195,902
Expenditures for property, plant and equipment	3,011	3,845	8,751	5,273
Goodwill	54,376	32,364	54,376	32,364	33,511
Military & Materials [Member]
Segment Reporting Information [Line Items]
Revenues	23,703	19,467	47,362	39,602
Inter-segment revenues	2,629	1,444	4,381	2,785
Segment earnings (loss)	(386)	3,425	2,576	7,146
Depreciation and amortization	991	622	1,954	1,200
Segment assets	90,573	71,088	90,573	71,088
Expenditures for property, plant and equipment	2,104	1,441	4,092	2,870
Goodwill	10,399	13,657	10,399	13,657	10,399
Advanced Products Group [Member]
Segment Reporting Information [Line Items]
Revenues	16,824	19,360	42,632	41,188
Inter-segment revenues	1,133	1,010	1,917	2,076
Segment earnings (loss)	1,470	3,775	7,478	7,186
Depreciation and amortization	1,043	812	1,980	1,625
Segment assets	103,506	86,773	103,506	86,773
Expenditures for property, plant and equipment	3,114	2,302	6,398	3,940
Equity investments	15,938	15,436	15,938	15,436
Goodwill	10,314	10,314	10,314	10,314	10,314
Eliminations [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	$ (4,998)	$ (3,383)	$ (8,414)	$ (6,354)