Revenue and Receivables - Disaggregate of Revenue by Reportable Segment and Revenue Category (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation Of Revenue [Line Items]
Revenue	$ 286,086	$ 247,744
Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	98,240	80,410
Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	97,326	78,198
Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	90,520	89,136
Network Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	237,941	202,217
Network Solutions [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	90,193	71,748
Network Solutions [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	70,952	54,622
Network Solutions [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	76,796	75,847
Services & Support [Member]
Disaggregation Of Revenue [Line Items]
Revenue	48,145	45,527
Services & Support [Member] | Subscriber Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	8,047	8,662
Services & Support [Member] | Optical Networking Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	26,374	23,576
Services & Support [Member] | Access & Aggregation Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 13,724	$ 13,289