Business Segment Information - Selected Financial Data for the Company's Business Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenue		$ 271.6	$ 275.9
Operating (loss) income		(2.8)	(39.2)
Expenditures for long-lived assets	[1]	155.3	142.1
Depreciation and amortization		77.4	112.9
Total assets		4,713.7	4,755.5	$ 4,755.5
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Total assets		920.0		1,030.2
Operating Segments | Network [Member]
Segment Reporting Information [Line Items]
Revenue		271.6	275.9
Operating (loss) income		3.8	(29.8)
Expenditures for long-lived assets	[1]	155.3	142.0
Depreciation and amortization		77.4	112.8
Total assets		3,661.7		3,597.2
Corporate [Member]
Segment Reporting Information [Line Items]
Operating (loss) income		(6.6)	(9.4)
Expenditures for long-lived assets	[1]	0.0	0.1
Depreciation and amortization		0.0	$ 0.1
Corporate and Elimination [Member]
Segment Reporting Information [Line Items]
Total assets		$ 132.0		$ 128.1

[1] Includes cost of acquisitions