Revenue - Schedule of Revenues Disaggregation by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenues	$ 448.9	$ 435.8
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	46.7	45.9
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	402.2	389.9
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(5.9)	(6.5)
Intersegment Eliminations [Member] | Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0
Intersegment Eliminations [Member] | Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0
Network [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	249.8	243.5
Network [Member] | Operating Segments | Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	5.6	7.4
Network [Member] | Operating Segments | Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	240.1	231.2
Network [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	4.1	4.9
IT Services and Hardware [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	205.0	198.8
IT Services and Hardware [Member] | Operating Segments | Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	41.1	38.5
IT Services and Hardware [Member] | Operating Segments | Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	162.1	158.7
IT Services and Hardware [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 1.8	$ 1.6