Financial Information of Company's Operation by Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012	Jun. 30, 2012
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	$ 145,170	$ 132,590	$ 403,351	$ 397,720
Segment earnings (loss)	18,003	16,974	49,532
Segment earnings				54,247
Interest expense	(449)	(48)	(708)	(184)
Other income, net	1,401	2,311	6,713	5,447
Income taxes	(2,861)	(4,967)	(13,844)	(13,006)
Net earnings	16,094	14,270	41,693	46,504
Depreciation and amortization	10,759	8,729	29,993	25,561
Segment assets	848,789	687,520	848,789	687,520	706,486
Expenditures for property, plant and equipment	4,321	9,703	17,498	32,771
Investment	10,977	10,528	10,977	10,528
Goodwill	122,330	81,099	122,330	81,099
Infrared Optics
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	52,886	50,678	149,852	148,236
Inter-segment revenues	730	769	1,881	2,473
Segment earnings (loss)	13,969	13,845	36,343
Segment earnings				37,672
Depreciation and amortization	2,032	1,985	6,264	6,319
Segment assets	206,664	205,151	206,664	205,151
Expenditures for property, plant and equipment	823	1,672	3,411	5,499
Goodwill	9,665	9,798	9,665	9,798
Near-Infrared Optics
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	35,821	36,629	113,463	100,143
Inter-segment revenues	(289)	480	679	1,675
Segment earnings (loss)	3,774	3,608	16,637
Segment earnings				8,554
Depreciation and amortization	4,228	4,255	12,900	11,666
Segment assets	302,813	261,927	302,813	261,927
Expenditures for property, plant and equipment	1,981	3,336	6,184	9,549
Goodwill	59,765	48,661	59,765	48,661
Military & Materials
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	28,869	30,054	74,164	91,480
Inter-segment revenues	695	852	3,033	5,763
Segment earnings (loss)	(550)	(958)	(3,773)
Segment earnings				64
Depreciation and amortization	2,018	1,409	5,092	4,516
Segment assets	147,564	118,429	147,564	118,429
Expenditures for property, plant and equipment	490	2,883	2,496	9,513
Goodwill	30,812	12,326	30,812	12,326
Advanced Products Group
Schedule Of Identifiable Assets By Segment [Line Items]
Revenues	27,594	15,229	65,872	57,861
Inter-segment revenues	1,303	902	3,863	2,819
Segment earnings (loss)	810	479	325
Segment earnings				7,957
Depreciation and amortization	2,481	1,080	5,737	3,060
Segment assets	191,748	102,013	191,748	102,013
Expenditures for property, plant and equipment	1,027	1,812	5,407	8,210
Investment	10,977	10,528	10,977	10,528
Goodwill	22,088	10,314	22,088	10,314
Eliminations
Schedule Of Identifiable Assets By Segment [Line Items]
Inter-segment revenues	$ (2,439)	$ (3,003)	$ (9,456)	$ (12,730)