Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 237,279
Foreign currency translation adjustment	632
Balance at end of period	237,911
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	176,519
Foreign currency translation adjustment	625
Balance at end of period	177,144
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,760
Foreign currency translation adjustment	7
Balance at end of period	$ 60,767