Business Segment Information - Selected Financial Data for the Company's Business Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenue		$ 439.5	$ 414.2	$ 875.3	$ 824.1
Operating (loss) income		(32.4)	30.4	(47.4)	63.0
Expenditures for long-lived assets	[1]	178.2	59.0	266.0	119.7
Depreciation and amortization		130.1	71.8	249.6	142.8
Total assets		4,208.3		4,208.3		$ 4,198.8
Operating Segments | Network [Member]
Segment Reporting Information [Line Items]
Revenue		247.0	241.0	490.5	483.8
Operating (loss) income		(18.9)	28.1	(22.0)	59.4
Expenditures for long-lived assets	[1]	171.1	52.8	252.6	107.8
Depreciation and amortization		103.4	61.6	196.8	122.4
Total assets		3,073.2		3,073.2		2,949.2
Operating Segments | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		199.0	179.9	397.8	353.7
Operating (loss) income		(5.1)	7.6	(10.0)	16.2
Expenditures for long-lived assets	[1]	7.1	6.2	13.4	11.9
Depreciation and amortization		26.6	10.2	52.6	20.3
Total assets		794.4		794.4		842.0
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue		(6.5)	(6.7)	(13.0)	(13.4)
Intersegment Eliminations [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Revenue		6.5	6.7	13.0	13.4
Intersegment Eliminations [Member] | Network [Member]
Segment Reporting Information [Line Items]
Revenue		4.8	4.9	9.7	9.7
Intersegment Eliminations [Member] | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		1.7	1.8	3.3	3.7
Corporate [Member]
Segment Reporting Information [Line Items]
Operating (loss) income		(8.4)	(5.3)	(15.4)	(12.6)
Depreciation and amortization		0.1	$ 0.0	0.2	$ 0.1
Corporate and Elimination [Member]
Segment Reporting Information [Line Items]
Total assets		$ 340.7		$ 340.7		$ 407.6

[1] Includes cost of Agile acquisition