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, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Revenue		$ 274.8	$ 272.8	$ 551.2	$ 544.4
Operating income (loss)		11.4	(2.2)	22.1	(5.0)
Expenditures for long-lived assets	[1]	143.1	132.7	286.3	288.0
Depreciation and amortization		87.3	80.3	171.9	157.7
Operating Segments | Network [Member]
Segment Reporting Information [Line Items]
Revenue		274.8	272.8	551.2	544.4
Operating income (loss)		17.6	4.2	33.9	8.0
Expenditures for long-lived assets	[1]	140.0	132.7	280.4	288.0
Depreciation and amortization		87.2	80.2	171.8	157.6
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income (loss)		(6.2)	(6.4)	(11.8)	(13.0)
Expenditures for long-lived assets	[1]	3.1	0.0	5.9	0.0
Depreciation and amortization		$ 0.1	$ 0.1	$ 0.1	$ 0.1

[1] Includes cost of acquisitions