Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Shares	Common Stock	Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Beginning balance, shares (in shares) at Jun. 30, 2019			76,315,000				(12,604,000)
Beginning balance at Jun. 30, 2019	$ 1,133,209		$ 382,423		$ (24,221)	$ 943,581	$ (168,574)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(708,000)				(251,000)
Share-based and deferred compensation activities	(49,211)		$ 59,043				$ (9,832)
Shares issued and related to Finisar acquisitions (in shares)			26,713,000
Shares issued related to Finisar acquisition	987,707		$ 987,707
Net earnings (loss)	(25,998)					(25,998)
Foreign currency translation adjustments	(13,019)				(13,019)
Pension adjustment, net of taxes	84				84
Ending balance, shares (in shares) at Sep. 30, 2019			103,736,000				(12,855,000)
Ending balance at Sep. 30, 2019	2,131,194		$ 1,429,173		(37,156)	917,583	$ (178,406)
Beginning balance, shares (in shares) at Jun. 30, 2019			76,315,000				(12,604,000)
Beginning balance at Jun. 30, 2019	1,133,209		$ 382,423		(24,221)	943,581	$ (168,574)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	(118,290)
Foreign currency translation adjustments	(28,258)
Change in fair value of interest rate swap, net of taxes	(27,798)
Pension adjustment, net of taxes	(167)
Ending balance, shares (in shares) at Mar. 31, 2020			104,278,000				(13,103,000)
Ending balance at Mar. 31, 2020	2,017,907		$ 1,459,354		(80,444)	825,291	$ (186,294)
Beginning balance, shares (in shares) at Sep. 30, 2019			103,736,000				(12,855,000)
Beginning balance at Sep. 30, 2019	2,131,194		$ 1,429,173		(37,156)	917,583	$ (178,406)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(307,000)				(175,000)
Share-based and deferred compensation activities	(6,393)		$ 12,007				$ (5,614)
Common stock repurchase (in shares)							(50,000)
Common stock repurchase	(1,625)						$ (1,625)
Net earnings (loss)	(98,213)					(98,213)
Foreign currency translation adjustments	24,590				24,590
Change in fair value of interest rate swap, net of taxes	3,609				3,609
Pension adjustment, net of taxes	(251)				(251)
Ending balance, shares (in shares) at Dec. 31, 2019			104,043,000				(13,080,000)
Ending balance at Dec. 31, 2019	2,065,697		$ 1,441,180		(9,208)	819,370	$ (185,645)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(235,000)				(23,000)
Share-based and deferred compensation activities	(17,525)		$ 18,174				$ (649)
Net earnings (loss)	5,921					5,921
Foreign currency translation adjustments	(39,829)				(39,829)
Change in fair value of interest rate swap, net of taxes	(31,407)				(31,407)
Pension adjustment, net of taxes	0
Ending balance, shares (in shares) at Mar. 31, 2020			104,278,000				(13,103,000)
Ending balance at Mar. 31, 2020	2,017,907		$ 1,459,354		(80,444)	825,291	$ (186,294)
Beginning balance, shares (in shares) at Jun. 30, 2020			105,916,000	0			(13,356,000)
Beginning balance at Jun. 30, 2020	2,076,803		$ 1,486,947	$ 0	(87,383)	876,552	$ (199,313)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(575,000)				(120,000)
Share-based and deferred compensation activities	$ (11,266)		$ 16,764				$ (5,498)
Shares issued (in shares)	10,698,000			2,300,000
Shares issued in underwritten public offering	$ 883,908		$ 438,589	$ 445,319
Net earnings (loss)	46,266					46,266
Foreign currency translation adjustments	35,524				35,524
Change in fair value of interest rate swap, net of taxes	(555)				(555)
Dividends	(6,535)					(6,535)
Ending balance, shares (in shares) at Sep. 30, 2020			117,189,000	2,300,000			(13,476,000)
Ending balance at Sep. 30, 2020	3,046,677		$ 1,942,300	$ 445,319	(52,414)	916,283	$ (204,811)
Beginning balance at Jun. 30, 2020	0
Beginning balance, shares (in shares) at Jun. 30, 2020			105,916,000	0			(13,356,000)
Beginning balance at Jun. 30, 2020	2,076,803		$ 1,486,947	$ 0	(87,383)	876,552	$ (199,313)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	215,258
Foreign currency translation adjustments	81,191
Change in fair value of interest rate swap, net of taxes	10,693
Pension adjustment, net of taxes	0
Ending balance, shares (in shares) at Mar. 31, 2021			118,370,000	2,300,000			(13,490,000)
Ending balance at Mar. 31, 2021	3,325,148		$ 2,011,210	$ 445,319	4,501	1,071,362	$ (207,244)
Beginning balance at Jun. 30, 2020	0
Mezzanine Equity
Accretion to redemption value of Series B shares issued in March 2021		$ 9
Ending balance (in shares) at Mar. 31, 2021		75,000
Ending balance at Mar. 31, 2021	716,200	$ 716,200
Beginning balance, shares (in shares) at Sep. 30, 2020			117,189,000	2,300,000			(13,476,000)
Beginning balance at Sep. 30, 2020	3,046,677		$ 1,942,300	$ 445,319	(52,414)	916,283	$ (204,811)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(854,000)				(11,000)
Share-based and deferred compensation activities	(42,215)		$ 43,533				$ (1,318)
Net earnings (loss)	87,900					87,900
Foreign currency translation adjustments	64,067				64,067
Change in fair value of interest rate swap, net of taxes	2,854				2,854
Dividends	(6,900)					(6,900)
Ending balance, shares (in shares) at Dec. 31, 2020			118,043,000	2,300,000			(13,487,000)
Ending balance at Dec. 31, 2020	3,236,813		$ 1,985,833	$ 445,319	14,507	997,283	$ (206,129)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based and deferred compensation activities (in shares)			(327,000)				(3,000)
Share-based and deferred compensation activities	$ (24,262)		$ 25,377				$ (1,115)
Shares issued (in shares)		75,000
Common stock repurchase (in shares)	0
Accretion to redemption value of Series B shares issued in March 2021	$ (9)					(9)
Net earnings (loss)	81,092					81,092
Foreign currency translation adjustments	(18,400)				(18,400)
Change in fair value of interest rate swap, net of taxes	8,394				8,394
Pension adjustment, net of taxes	0
Dividends	(7,004)					(7,004)
Ending balance, shares (in shares) at Mar. 31, 2021			118,370,000	2,300,000			(13,490,000)
Ending balance at Mar. 31, 2021	3,325,148		$ 2,011,210	$ 445,319	$ 4,501	$ 1,071,362	$ (207,244)
Mezzanine Equity
Series B shares issued in March 2021		$ 716,087
Dividends (in shares)		0
Dividends		$ 104
Ending balance (in shares) at Mar. 31, 2021		75,000
Ending balance at Mar. 31, 2021	$ 716,200	$ 716,200