Summary of Revenues from Contracts with Customers by Major Product Line (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Major Customer [Line Items]
Net sales	$ 1,726,540	$ 1,664,170	$ 3,304,250	$ 3,147,276
Operating Segments | CPE
Revenue, Major Customer [Line Items]
Net sales	1,008,131	1,155,883	1,883,357	2,210,939
Operating Segments | CPE | Broadband
Revenue, Major Customer [Line Items]
Net sales	405,082		728,367
Operating Segments | CPE | Video
Revenue, Major Customer [Line Items]
Net sales	603,049		1,154,990
Operating Segments | N&C
Revenue, Major Customer [Line Items]
Net sales	549,496	$ 510,972	1,087,760	$ 941,408
Operating Segments | N&C | Network & Cloud
Revenue, Major Customer [Line Items]
Net sales	479,386		932,387
Operating Segments | N&C | Software And Services [Member]
Revenue, Major Customer [Line Items]
Net sales	70,110		155,373
Operating Segments | Enterprise
Revenue, Major Customer [Line Items]
Net sales	172,240		342,154
Operating Segments | Other Segments
Revenue, Major Customer [Line Items]
Net sales	$ (3,327)		$ (9,021)