Business Combinations (Summary of Final Allocation of Tangible and Identifiable Intangible Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018	Oct. 27, 2017	Jul. 14, 2017
Final Allocation
Goodwill	$ 137,799	$ 139,082
Data Center Business
Final Allocation
Accounts receivables			$ 33,488
Inventories			19,934
Prepaid expenses and other current assets			988
Property and equipment			20,220
Other assets			4,734
Accounts payable and accrued expenses			(16,494)
Deferred revenue			(33,025)
Total tangible assets acquired and liabilities assumed			29,845
Identifiable intangible assets			32,800
Goodwill			21,692
Total intangible assets acquired			54,492
Total net assets acquired			$ 84,337
Campus Fabric Business
Final Allocation
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