Segment Information - Narratives (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Customer segment country	Dec. 31, 2018 USD ($) Customer country	Dec. 31, 2017 USD ($) Customer country
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Unallocated Corporate Expenses	$ 209,929	$ 214,220	$ 240,697
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Unallocated Corporate Expenses	$ 4,532	$ 3,769	$ 20,767	[1]
Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Number Of Customers Accounting For More Than Ten Percent Of Revenue Other Than Comcast | Customer			0
Non-US [Member] | Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Number Of Countries Accounting For More Than Ten Percent of Non United States Revenue | country	0	0	0
Concentration Risk, Percentage	10.00%
Avid Technology Inc. [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Litigation Settlement, Expense			$ 8,000
Operating expense [Member] | Change in Accounting Method Accounted for as Change in Estimate [Member]
Segment Reporting Information [Line Items]
Impact of methodology change on Video and Cable Access Segments			5,900
Comcast [Member] | Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	10.00%	10.00%
Comcast [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	23.00%	15.00%
Number Of Customers Accounting For More Than Ten Percent of Revenue | Customer	1	1
French TVN Acquisition, Integration-related Expenses and French Voluntary Costs | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Unallocated Corporate Expenses			$ 7,900

[1] For the year ended December 31, 2017, the unallocated corporate expenses included acquisition- and integration-related costs, French VDP costs (see Note 11, “Restructuring and Related charges,” for more information on French VDP) and Cable Access product line inventory obsolescence costs, totaling $7.9 million. In addition, in fiscal 2017, the unallocated corporate expenses included $8.0 million of Avid litigation settlement cost and associated legal fees (see Note 20, “Legal Proceedings,” for more information). The remaining unallocated corporate expenses for all years presented above include primarily other restructuring charges and excess facilities charges.