Summary of Significant Accounting Policies - Schedule of Revenue Disaggregated by Revenue Type, Geographic Region and Customer (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Total revenue	$ 262,168	$ 255,134	$ 526,568	$ 508,253
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%	58.00%	54.00%	58.00%
Telecommunications
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	19.00%	18.00%	20.00%	18.00%
Other
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	26.00%	24.00%	26.00%	24.00%
Americas (principally the U.S.)
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	85.00%	85.00%	85.00%	86.00%
Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	11.00%	11.00%	11.00%	10.00%
Asia Pacific
Disaggregation Of Revenue [Line Items]
Percentage of total revenue	4.00%	4.00%	4.00%	4.00%
SaaS and Related Solutions
Disaggregation Of Revenue [Line Items]
Total revenue	$ 230,712	$ 228,248	$ 465,689	$ 455,267
Software and Services
Disaggregation Of Revenue [Line Items]
Total revenue	20,068	15,033	38,504	29,812
Maintenance
Disaggregation Of Revenue [Line Items]
Total revenue	$ 11,388	$ 11,853	$ 22,375	$ 23,174