Debt - Additional Information (Detail)			12 Months Ended
	Jul. 07, 2020 USD ($)	Sep. 24, 2019 USD ($) d	Jun. 30, 2020 USD ($) $ / shares	Jun. 30, 2019 USD ($)	Oct. 23, 2019 USD ($)	Jun. 30, 2018	Aug. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Amortization period			3 years	3 years
Available credit under lines of credit			$ 374,600,000
Weighted average interest rate of total borrowings			3.40%	1.60%
0.25% Convertible Senior Note Due 2022
Line of Credit Facility [Line Items]
Debt instrument, interest rate			0.25%			0.25%
Debt instrument, unamortized discount			$ 26,800,000
Aggregate principal amount							$ 345,000,000
Debt instrument conversion, shares issued per $1,000 principal amount			0.02125
Debt instrument conversion, principal amount of each note converted			$ 1,000
Debt instrument conversion, conversion price per share | $ / shares			$ 47.06
Debt instrument conversion, If-converted value of notes			$ 346,200,000	$ 268,000,000.0
Effective interest rate			4.50%	4.50%		4.50%
0.50% Finisar Convertible Notes
Line of Credit Facility [Line Items]
Obligated to repay outstanding principal in quarterly installments, percentage		100.00%
Debt instrument, interest rate			0.50%
Aggregate principal amount		$ 560,100,000
Debt instrument, repurchase amount					$ 561,100,000
Line of credit, outstanding			$ 14,900,000
Bank of America, N.A.
Line of Credit Facility [Line Items]
Letter of credit sub-facility maximum borrowing capacity		25,000,000.0
Swing loan sub-facility maximum initial borrowing capacity		20,000,000.0
Senior Secured Credit Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount		2.425
Term A Loan Facility
Line of Credit Facility [Line Items]
Proceeds from term loan		561,000,000.0
Term A Loan Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount		$ 1,255,000,000
Debt instrument term		5 years
Obligated to repay outstanding principal in quarterly installments, percentage		1.25%
Term B Loan Facility | Subsequent Event
Line of Credit Facility [Line Items]
Repayment of Term B Loan Facility	$ 715,000,000
Term B Loan Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount		$ 720,000,000
Debt instrument term		7 years
Obligated to repay outstanding principal in quarterly installments, percentage		0.25%
Revolving Credit Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount		$ 450,000,000
Debt instrument term		5 years
New Senior Credit Facilities
Line of Credit Facility [Line Items]
Debt issuance costs incurred			69,800,000
Debt issuance costs capitalized			65,800,000
Debt extinguishment costs			4,000,000.0
Debt issuance costs			8,800,000
Debt instrument, unamortized discount			$ 56,900,000
New Senior Credit Facilities | Fifth Fiscal Quarter Through Eighth Fiscal Quarter After Closing Date
Line of Credit Facility [Line Items]
Leverage ratio		4.50
New Senior Credit Facilities | Subsequent Fiscal Quarter
Line of Credit Facility [Line Items]
Leverage ratio		4.00
New Senior Credit Facilities | Minimum
Line of Credit Facility [Line Items]
Interest coverage ratio		3.00
Amortization period			5 years
New Senior Credit Facilities | Maximum
Line of Credit Facility [Line Items]
Amortization period			7 years
New Senior Credit Facilities | Maximum | First Four Fiscal Quarters After Closing Date
Line of Credit Facility [Line Items]
Leverage ratio		5.00
New Senior Credit Facilities | Federal Funds Rate
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate		0.50%
New Senior Credit Facilities | Euro Rate Option
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate		1.00%
New Senior Credit Facilities | 0.25% Convertible Senior Note Due 2022 | II-VI Notes
Line of Credit Facility [Line Items]
Number of days prior to maturity of outstanding | d		120
Debt instrument, interest rate		0.25%