Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 237,279
Foreign currency translation adjustment	3,291
Balance at end of period	240,570
Video [Member]
Goodwill [Line Items]
Balance at beginning of period	176,519
Foreign currency translation adjustment	3,261
Balance at end of period	179,780
Cable Edge [Member]
Goodwill [Line Items]
Balance at beginning of period	60,760
Foreign currency translation adjustment	30
Balance at end of period	$ 60,790