Summary of Significant Accounting Policies - Schedule of Revenue Disaggregated by Revenue Type, Geographic Region and Customer (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 273,308	$ 263,209	$ 799,876	$ 771,462
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
Broadband/Cable/Satellite
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	55.00%	56.00%	55.00%	57.00%
Telecommunications
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	20.00%	20.00%	19.00%	19.00%
Other
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	25.00%	24.00%	26.00%	24.00%
Americas (principally the U.S.)
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	86.00%	85.00%	85.00%	85.00%
Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	10.00%	12.00%	11.00%	11.00%
Asia Pacific
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	4.00%	3.00%	4.00%	4.00%
SaaS and Related Solutions
Disaggregation Of Revenue [Line Items]
Total revenue	$ 238,614	$ 231,418	$ 704,303	$ 686,685
Software and Services
Disaggregation Of Revenue [Line Items]
Total revenue	23,123	19,518	61,627	49,330
Maintenance
Disaggregation Of Revenue [Line Items]
Total revenue	$ 11,571	$ 12,273	$ 33,946	$ 35,447