Business Segment Information - Selected Financial Data for the Company's Business Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenue		$ 448.9	$ 435.8
Operating (loss) income		(43.2)	(15.0)
Expenditures for long-lived assets	[1]	146.4	87.8
Depreciation and amortization		133.3	119.5
Total assets		4,402.9		$ 4,435.6
Operating Segments | Network [Member]
Segment Reporting Information [Line Items]
Revenue		249.8	243.5
Operating (loss) income		(29.1)	(3.1)
Expenditures for long-lived assets	[1]	140.4	81.5
Depreciation and amortization		108.9	93.4
Total assets		3,276.5		3,218.5
Operating Segments | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		205.0	198.8
Operating (loss) income		(5.8)	(4.9)
Expenditures for long-lived assets	[1]	5.9	6.3
Depreciation and amortization		24.3	26.0
Total assets		982.9		812.2
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue		(5.9)	(6.5)
Intersegment Eliminations [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Revenue		5.9	6.5
Intersegment Eliminations [Member] | Network [Member]
Segment Reporting Information [Line Items]
Revenue		4.1	4.9
Intersegment Eliminations [Member] | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		1.8	1.6
Corporate [Member]
Segment Reporting Information [Line Items]
Operating (loss) income		(8.3)	(7.0)
Expenditures for long-lived assets	[1]	0.1	0.0
Depreciation and amortization		0.1	$ 0.1
Corporate and Elimination [Member]
Segment Reporting Information [Line Items]
Total assets		$ 143.5		$ 404.9

[1] Includes cost of acquisitions