Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 197,781
Goodwill, Acquired During Period	41,670
Foreign currency translation adjustment	(2,172)
Balance at end of period	237,279
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	136,904
Goodwill, Acquired During Period	41,670
Foreign currency translation adjustment	(2,055)
Balance at end of period	176,519
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,877
Foreign currency translation adjustment	(117)
Balance at end of period	$ 60,760