Revenue - Schedule of Revenues Disaggregation by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Revenues	$ 435.8	$ 409.9
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(6.5)	(6.7)
Network [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	243.5	242.8
Network [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	4.9	4.8
IT Services and Hardware [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	198.8	173.8
IT Services and Hardware [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	1.6	1.9
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	45.9	39.3
Transferred at Point in Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0
Transferred at Point in Time [Member] | Network [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	7.4	5.9
Transferred at Point in Time [Member] | IT Services and Hardware [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	38.5	33.4
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	389.9	370.6
Transferred over Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0
Transferred over Time [Member] | Network [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	231.2	232.1
Transferred over Time [Member] | IT Services and Hardware [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 158.7	$ 138.5