Revenue - Schedule of Revenues Disaggregation by Product and Service Lines (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenues	$ 448.9	$ 435.8
Operating Segments | Network [Member]
Disaggregation Of Revenue [Line Items]
Revenues	249.8	243.5
Operating Segments | Network [Member] | Data [Member]
Disaggregation Of Revenue [Line Items]
Revenues	136.2	126.1
Operating Segments | Network [Member] | Video [Member]
Disaggregation Of Revenue [Line Items]
Revenues	48.6	48.6
Operating Segments | Network [Member] | Voice [Member]
Disaggregation Of Revenue [Line Items]
Revenues	56.9	59.3
Operating Segments | Network [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues	8.1	9.5
Operating Segments | IT Services and Hardware [Member]
Disaggregation Of Revenue [Line Items]
Revenues	205.0	198.8
Operating Segments | IT Services and Hardware [Member] | Consulting
Disaggregation Of Revenue [Line Items]
Revenues	84.7	83.4
Operating Segments | IT Services and Hardware [Member] | Cloud
Disaggregation Of Revenue [Line Items]
Revenues	26.6	24.6
Operating Segments | IT Services and Hardware [Member] | Communications
Disaggregation Of Revenue [Line Items]
Revenues	56.2	54.9
Operating Segments | IT Services and Hardware [Member] | Infrastructure Solutions
Disaggregation Of Revenue [Line Items]
Revenues	37.5	35.9
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(5.9)	(6.5)
Intersegment Eliminations [Member] | Network [Member]
Disaggregation Of Revenue [Line Items]
Revenues	4.1	4.9
Intersegment Eliminations [Member] | IT Services and Hardware [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 1.8	$ 1.6