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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenue		$ 272.8	$ 275.3	$ 544.4	$ 551.2
Operating (loss) income		(2.2)	(8.0)	(5.0)	(47.2)
Expenditures for long-lived assets	[1]	132.7	153.5	288.0	295.6
Depreciation and amortization		80.3	90.4	157.7	203.3
Total assets		4,845.5		4,845.5		$ 4,755.5
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Total assets		915.0		915.0		1,030.2
Operating Segments | Network [Member]
Segment Reporting Information [Line Items]
Revenue		272.8	275.3	544.4	551.2
Operating (loss) income		4.2	(4.0)	8.0	(33.8)
Expenditures for long-lived assets	[1]	132.7	153.4	288.0	295.4
Depreciation and amortization		80.2	90.3	157.6	203.1
Total assets		3,701.5		3,701.5		3,597.2
Corporate [Member]
Segment Reporting Information [Line Items]
Operating (loss) income		(6.4)	(4.0)	(13.0)	(13.4)
Expenditures for long-lived assets	[1]	0.0	0.1	0.0	0.2
Depreciation and amortization		0.1	$ 0.1	0.1	$ 0.2
Corporate and Elimination [Member]
Segment Reporting Information [Line Items]
Total assets		$ 229.0		$ 229.0		$ 128.1

[1] Includes cost of acquisitions