Financial Information of Company's Operation by Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues	$ 187,921	$ 173,555	$ 171,765	$ 150,020	$ 154,030	$ 143,940	$ 125,107	$ 127,998	$ 683,261	$ 551,075	$ 516,403
Segment earnings (loss)									46,486	71,491	81,522
Interest expense	(1,415)	(1,412)	(1,169)	(483)	(452)	(449)	(223)	(36)	(4,479)	(1,160)	(212)
Other income, net									3,634	7,155	7,168
Income taxes	(1,502)	(494)	(2,086)	(3,243)	(4,922)	(2,861)	(6,721)	(4,262)	(7,325)	(18,766)	(17,760)
Earnings (loss) from discontinued operation			131	2	(4,226)	(166)	(608)	(1,789)	133	(6,789)	(9,443)
Net earnings					10,238	16,094	12,467	13,132	38,449	51,931	61,275
Depreciation and amortization									53,098	40,792	34,523
Segment assets	1,071,926				863,802				1,071,926	863,802
Expenditures for property, plant and equipment									29,220	25,205	42,797
Total carrying value of equity method investment	11,589				11,203				11,589	11,203
Goodwill	196,145				123,352				196,145	123,352	80,748
Eliminations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Inter-segment revenues									(17,479)	(13,678)	(17,193)
Infrared Optics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									209,658	203,319	201,611
Inter-segment revenues									1,608	2,618	3,174
Segment earnings (loss)									40,736	49,457	51,095
Depreciation and amortization									9,174	8,423	8,480
Segment assets	231,874				238,700				231,874	238,700
Expenditures for property, plant and equipment									9,719	5,812	8,072
Goodwill	9,754				9,677				9,754	9,677	9,612
Near-Infrared Optics | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									144,677	154,852	140,001
Inter-segment revenues									2,406	896	2,135
Segment earnings (loss)									9,814	19,628	14,060
Depreciation and amortization									16,764	17,286	15,803
Segment assets	295,953				307,431				295,953	307,431
Expenditures for property, plant and equipment									8,171	9,170	12,249
Goodwill	60,408				60,269				60,408	60,269	48,496
Military & Materials | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									98,324	97,116	100,235
Inter-segment revenues									6,514	4,853	7,589
Segment earnings (loss)									12,851	656	7,925
Depreciation and amortization									8,111	7,023	5,957
Segment assets	117,730				139,923				117,730	139,923
Expenditures for property, plant and equipment									5,539	3,909	11,983
Goodwill	30,712				30,712				30,712	30,712	12,326
Advanced Products Group | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									115,394	95,788	74,556
Inter-segment revenues									6,388	5,311	4,295
Segment earnings (loss)									9,419	1,750	8,442
Depreciation and amortization									9,947	8,060	4,283
Segment assets	175,986				177,748				175,986	177,748
Expenditures for property, plant and equipment									3,525	6,314	10,493
Total carrying value of equity method investment	11,589				11,203				11,589	11,203
Goodwill	22,178				22,694				22,178	22,694	10,314
Active Optical Products | Operating Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Revenues									115,208
Inter-segment revenues									563
Segment earnings (loss)									(26,334)
Depreciation and amortization									9,102
Segment assets	250,383								250,383
Expenditures for property, plant and equipment									2,266
Goodwill	$ 73,093								$ 73,093