Segment Reporting - Financial Information of Company's Operation by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues	$ 627,041	$ 342,496	$ 1,633,781	$ 999,768
Operating income (loss)	69,036	31,130	(28,017)	107,949
Interest expense	(28,530)	(5,647)	(63,888)	(16,811)
Other income (expense), net	(7,168)	1,532	(12,734)	2,946
Income taxes	(27,417)	(2,377)	(13,651)	(14,595)
Net earnings (loss)	5,921	24,638	(118,290)	79,489
Depreciation and amortization	38,024	23,161	147,124	67,627
Expenditures for property, plant & equipment	27,687	34,783	107,975	108,170
Segment assets	5,106,823		5,106,823		$ 1,953,773
Goodwill	1,281,762		1,281,762		319,778
Photonic Solutions
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues	417,769	166,473	1,019,518	461,323
Inter-segment revenues	6,899	3,115	21,245	8,451
Operating income (loss)	48,706	20,723	793	59,722
Interest expense	0
Depreciation and amortization	14,272	6,795	76,262	19,456
Expenditures for property, plant & equipment	8,083	11,177	38,785	34,451
Segment assets	3,410,742		3,410,742
Goodwill	1,095,489		1,095,489		134,057
Compound Semiconductors
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues	209,272	176,023	592,212	538,445
Inter-segment revenues	36,492	20,693	116,548	59,599
Operating income (loss)	24,894	14,314	42,580	59,237
Interest expense	0
Depreciation and amortization	23,752	16,366	67,119	48,171
Expenditures for property, plant & equipment	19,604	23,606	66,426	73,719
Segment assets	1,696,081		1,696,081
Goodwill	186,273		186,273		$ 185,721
Unallocated & Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues	0	0	22,051	0
Inter-segment revenues	(43,391)	(23,808)	(137,793)	(68,050)
Operating income (loss)	(4,563)	$ (3,907)	(71,389)	$ (11,010)
Interest expense	0
Depreciation and amortization			3,743
Expenditures for property, plant & equipment	$ 0		$ 2,764