Business Combinations (Summary of Final Allocation of Tangible and Identifiable Intangible Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Oct. 27, 2017	Jul. 14, 2017
Business Acquisition [Line Items]
Goodwill	$ 331,159	$ 138,577	$ 139,082
Data Center Business
Business Acquisition [Line Items]
Accounts receivables				$ 33,488
Inventories				19,934
Prepaid expenses and other current assets				988
Property and equipment				19,442
Other assets				4,734
Accounts payable and accrued expenses				(16,494)
Deferred revenue				(33,025)
Total tangible assets acquired and liabilities assumed				29,067
Identifiable intangible assets				32,800
Goodwill				22,470
Total intangible assets acquired				55,270
Total net assets acquired				$ 84,337
Campus Fabric Business
Business Acquisition [Line Items]
Accounts receivables					$ 19,527
Inventories					14,165
Prepaid expenses and other current assets					240
Property and equipment					5,406
Other assets					7,009
Accounts payable and accrued expenses					(31,670)
Deferred revenue					(8,994)
Other long-term liabilities					(5,849)
Total tangible assets acquired and liabilities assumed					(166)
Identifiable intangible assets					41,300
In-process research and development					2,400
Goodwill					35,892
Total intangible assets acquired					79,592
Total net assets acquired					$ 79,426