Summary of Company's Revenues by Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2017	[1],[2],[3],[4]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	[5],[6]	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Major Customer [Line Items]
Net sales	$ 1,738,593		$ 1,728,524	$ 1,664,170	$ 1,483,105	$ 1,759,223		$ 1,725,145	$ 1,730,044	$ 1,614,706	$ 6,614,392	$ 6,829,118	$ 4,798,332
Operating Segments | CPE
Revenue, Major Customer [Line Items]
Net sales											4,475,670	4,747,445	3,136,585
Operating Segments | CPE | Broadband
Revenue, Major Customer [Line Items]
Net sales											1,808,600	1,683,491	1,452,164
Operating Segments | CPE | Video
Revenue, Major Customer [Line Items]
Net sales											2,667,070	3,063,954	1,684,421
Operating Segments | N&C
Revenue, Major Customer [Line Items]
Net sales											2,094,113	2,111,708	1,661,594
Operating Segments | N&C | Network & Cloud
Revenue, Major Customer [Line Items]
Net sales											1,747,936	1,789,097	1,390,283
Operating Segments | N&C | Software And Services [Member]
Revenue, Major Customer [Line Items]
Net sales											346,177	322,611	271,311
Operating Segments | Enterprise
Revenue, Major Customer [Line Items]
Net sales											45,749
Operating Segments | Other Segments
Revenue, Major Customer [Line Items]
Net sales											$ (1,140)	$ (30,035)	$ 153

[1] During 2017, the Company recorded a foreign currency remeasurement loss of $10.5 million related primarily to a deferred income tax liability, in the United Kingdom. This deferred income tax liability is denominated in GBP. The foreign currency remeasurement gain derives from the remeasurement of the GBP deferred income tax liability to the USD, since the date of the acquisition.

[2] For the quarter ended December 31, 2017, the Company recorded an increase to net sales of $8.1 million, to reverse previous quarters reduction in net sales in connection with Warrants.

[3] In the fourth quarter of 2017, the Company recorded acquisition costs of $61.5 million related to the cash settlement of stock-based awards held by transferring employees.

[4] In the fourth quarter of 2017, the Company recorded partial impairments of goodwill and indefinite-lived tradenames of $51.2 million and $3.8 million, respectively, acquired in our ActiveVideo acquisition and included as part of our Cloud TV reporting unit, of which $19.3 million is attributable to noncontrolling interest.

[5] For the quarter ended December 31, 2016, the Company recorded $16.4 million as a reduction to net sales in connection with Warrants.

[6] In the fourth quarter of 2016, the Company recorded foreign currency remeasurement gains of approximately $16 million related to the remeasurement of net deferred income tax liabilities in the U.K. where the functional currency is the U.S. dollar. Approximately $8 million resulted from changes in exchange rates prior to the 4th quarter in 2016 and was considered the correction of an immaterial misstatement of interim financial statements in 2016. In accordance with ASC Topic 250, Accounting Changes and Error Corrections, the Company evaluated the impact of the 4th quarter adjustment on its previously issued interim financial statements in 2016 and concluded that the results of operations for these periods were not materially misstated and accordingly the correction was recorded in the 4th quarter.