Restructuring, Acquisition and Integration (Detail Textuals) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($) Employee	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Employee	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) Employee	Dec. 31, 2016 USD ($) Employee
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 36,103
Integration, acquisition and restructuring	$ 5,046	$ 10,836	41,546	$ 30,622
Ruckus Wireless and ICX Switch business (Ruckus Networks)
Restructuring Cost and Reserve [Line Items]
Acquisition expense	100	2,000	700	6,700
Employee severance & termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 4,300		$ 35,979		$ 13,300	$ 96,300
Total number of positions affected by the restructuring plan | Employee	1,069		1,069		195	1,545
Contractual obligations and other
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 124
Leased properties, remaining expiration terms			2021
Integration Related
Restructuring Cost and Reserve [Line Items]
Integration, acquisition and restructuring	$ 700	$ 300	$ 4,700	$ 1,900