Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 197,781
Goodwill, Acquired During Period	41,670
Foreign currency translation adjustment	429
Balance at end of period	239,880
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	136,904
Goodwill, Acquired During Period	41,670
Foreign currency translation adjustment	515
Balance at end of period	179,089
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,877
Foreign currency translation adjustment	(86)
Balance at end of period	$ 60,791