Segment and Geographic Reporting - Financial Information of Company's Operation by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Net revenues	$ 808,006	$ 783,232	$ 786,569	$ 728,084	$ 746,290	$ 627,041	$ 666,331	$ 340,409	$ 3,105,891	$ 2,380,071	$ 1,362,496
Inter-segment revenues									0	0	0
Operating income (loss)									402,119	39,479	148,668
Interest expense	(14,066)	(13,034)	(15,585)	(17,214)	(25,521)	(28,530)	(28,390)	(6,968)	(59,899)	(89,409)	(22,417)
Other income, net	10,124	21,432	3,153	(24,339)	(1,264)	(7,168)	(487)	(5,079)	10,370	(13,998)	2,562
Income taxes	(10,957)	(12,387)	(18,383)	(13,311)	10,550	(27,417)	9,242	4,524	(55,038)	(3,101)	(21,296)
Net Earnings (Loss)	82,294	$ 81,092	$ 87,900	$ 46,266	51,261	$ 5,921	$ (98,213)	$ (25,998)	297,552	(67,029)	107,517
Depreciation and amortization									270,069	220,882	92,365
Expenditures for property, plant & equipment									146,337	136,877	128,750
Segment assets	6,512,650				5,234,714				6,512,650	5,234,714	1,953,773
Goodwill	1,296,727				1,239,009				1,296,727	1,239,009	319,778
Photonic Solutions
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	1,053,028				1,052,494				1,053,028	1,052,494	134,057
Compound Semiconductors
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Goodwill	243,699				186,515				243,699	186,515	185,721
Operating Segments | Photonic Solutions
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Net revenues									2,038,284	1,536,790	638,889
Inter-segment revenues									35,358	31,515	12,568
Operating income (loss)									207,652	49,930	81,898
Interest expense									0	0	0
Other income, net									0	0	0
Income taxes									0	0	0
Net Earnings (Loss)									0	0	0
Depreciation and amortization									161,208	112,203	26,273
Expenditures for property, plant & equipment									87,304	45,795	44,851
Segment assets	4,231,289				3,502,467				4,231,289	3,502,467	681,610
Goodwill	1,053,028				1,052,494				1,053,028	1,052,494	134,057
Operating Segments | Compound Semiconductors
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Net revenues									1,067,607	821,230	723,607
Inter-segment revenues									244,407	164,884	94,405
Operating income (loss)									221,239	62,279	82,414
Interest expense									0	0	0
Other income, net									0	0	0
Income taxes									0	0	0
Net Earnings (Loss)									0	0	0
Depreciation and amortization									108,861	104,936	66,092
Expenditures for property, plant & equipment									59,033	88,318	83,899
Segment assets	2,281,361				1,732,247				2,281,361	1,732,247	1,272,163
Goodwill	243,699				186,515				243,699	186,515	185,721
Unallocated & Other
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Net revenues									0	22,051	0
Inter-segment revenues									(279,765)	(196,399)	(106,973)
Operating income (loss)									(26,772)	(72,730)	(15,643)
Interest expense									0	0	0
Other income, net									0	0	0
Income taxes									0	0	0
Net Earnings (Loss)									0	0	0
Depreciation and amortization									0	3,743	0
Expenditures for property, plant & equipment									0	2,764	0
Segment assets	0				0				0	0	0
Goodwill	$ 0				$ 0				$ 0	$ 0	$ 0