Property, Plant and Equipment, Net - Components (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
Property, Plant and Equipment, Net
Total property, plant and equipment	$ 2,103.4		$ 2,103.4		$ 2,033.4
Less accumulated depreciation	(1,391.8)		(1,391.8)		(1,311.1)
Plant, Property and Equipment, Net	711.6		711.6		722.3
Depreciation expense	44.4	$ 42.3	88.8	$ 83.5
Gain on sale of operating assets, net	0.6		1.0
Distribution facilities
Property, Plant and Equipment, Net
Total property, plant and equipment	1,286.4		1,286.4		1,238.3
Customer premise equipment
Property, Plant and Equipment, Net
Total property, plant and equipment	269.4		269.4		267.7
Head-end equipment
Property, Plant and Equipment, Net
Total property, plant and equipment	241.8		241.8		228.5
Computer equipment and software
Property, Plant and Equipment, Net
Total property, plant and equipment	143.9		143.9		132.5
Telephony infrastructure
Property, Plant and Equipment, Net
Total property, plant and equipment	52.3		52.3		52.4
Buildings and leasehold improvements
Property, Plant and Equipment, Net
Total property, plant and equipment	32.4		32.4		32.1
Vehicles
Property, Plant and Equipment, Net
Total property, plant and equipment	22.1		22.1		23.7
Office and technical equipment
Property, Plant and Equipment, Net
Total property, plant and equipment	19.0		19.0		18.9
Land
Property, Plant and Equipment, Net
Total property, plant and equipment	4.4		4.4		4.4
Construction in progress (including material inventory and other)
Property, Plant and Equipment, Net
Total property, plant and equipment	$ 31.7		$ 31.7		$ 34.9