Restructuring, Acquisition and Integration - Additional Information (Detail) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($) Employee	Mar. 31, 2018 USD ($) Employee	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) Facility Employee	Dec. 31, 2016 USD ($) Position
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 21,200			$ 31,783
Integration, acquisition and restructuring	22,844		$ 9,690	36,499	$ 19,785
Ruckus Wireless and ICX Switch business (Ruckus Networks)
Restructuring Cost and Reserve [Line Items]
Acquisition expense	600		2,300	700	4,700
Employee severance & termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 15,500	$ 10,500		31,664		$ 13,300	$ 96,300
Total number of positions affected by the restructuring plan	150	850				195	1,545
Contractual obligations and other
Restructuring Cost and Reserve [Line Items]
Restructuring charges				119		$ 5,700
Leased properties, remaining expiration terms		2021
Number of facilities | Facility						3
One-time Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 5,700
Integration Related
Restructuring Cost and Reserve [Line Items]
Integration, acquisition and restructuring	$ 1,100		$ 300	$ 4,000	$ 1,600