Plant, Property and Equipment, Net - Components (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Plant, Property and Equipment, Net
Total property, plant and equipment	$ 2,379.9		$ 2,379.9		$ 2,202.2
Less accumulated depreciation	(1,592.6)		(1,592.6)		(1,476.4)
Plant, Property and Equipment, Net	787.3		787.3		725.8
Depreciation expense	48.9	$ 44.9	141.1	$ 133.7
Losses (gains) on sale of operating assets, net	0.4	$ 0.0	0.3	$ (1.0)
Distribution facilities
Plant, Property and Equipment, Net
Total property, plant and equipment	1,446.8		1,446.8		1,341.1
Customer premise equipment
Plant, Property and Equipment, Net
Total property, plant and equipment	272.3		272.3		272.3
Head-end equipment
Plant, Property and Equipment, Net
Total property, plant and equipment	287.1		287.1		256.7
Computer equipment and software
Plant, Property and Equipment, Net
Total property, plant and equipment	174.4		174.4		156.4
Telephony infrastructure
Plant, Property and Equipment, Net
Total property, plant and equipment	48.0		48.0		52.4
Buildings and leasehold improvements
Plant, Property and Equipment, Net
Total property, plant and equipment	33.2		33.2		33.4
Vehicles
Plant, Property and Equipment, Net
Total property, plant and equipment	25.2		25.2		22.9
Office and technical equipment
Plant, Property and Equipment, Net
Total property, plant and equipment	18.9		18.9		19.1
Land
Plant, Property and Equipment, Net
Total property, plant and equipment	4.4		4.4		4.4
Construction in progress (including material inventory and other)
Plant, Property and Equipment, Net
Total property, plant and equipment	$ 69.6		$ 69.6		$ 43.5