Revenue from Contracts with Customers - Revenue by Service Offering (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue from Contracts with Customers
Other revenue	$ 7.3	$ 7.1	$ 14.5	$ 14.7
Total revenue	158.8	172.6	320.3	344.8
Subscription services
Revenue from Contracts with Customers
Revenue	146.5	160.4	295.5	319.8
Other business services
Revenue from Contracts with Customers
Revenue	5.0	5.1	10.3	10.3
Other business services - Wholesale and colocation lease revenue
Revenue from Contracts with Customers
Revenue	4.7	4.9	9.7	9.6
Residential subscription | Subscription services
Revenue from Contracts with Customers
Revenue	118.5	132.2	239.5	263.8
Residential subscription | HSD
Revenue from Contracts with Customers
Revenue	85.7	88.0	172.6	174.8
Residential subscription | Video
Revenue from Contracts with Customers
Revenue	28.3	38.7	57.6	77.9
Residential subscription | Telephony
Revenue from Contracts with Customers
Revenue	4.5	5.5	9.3	11.1
Business subscription | Subscription services
Revenue from Contracts with Customers
Revenue	28.0	28.2	56.0	56.0
Business subscription | HSD
Revenue from Contracts with Customers
Revenue	19.3	18.7	38.6	37.1
Business subscription | Video
Revenue from Contracts with Customers
Revenue	2.5	2.9	5.0	5.8
Business subscription | Telephony
Revenue from Contracts with Customers
Revenue	$ 6.2	$ 6.6	$ 12.4	$ 13.1