Revenue from Contracts with Customers - Revenue by Service Offering (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from Contracts with Customers
Other revenue	$ 7.5	$ 7.4	$ 22.0	$ 22.1
Total revenue	158.0	173.1	478.3	517.9
Subscription services
Revenue from Contracts with Customers
Revenue	146.0	160.3	441.5	480.1
Other business services
Revenue from Contracts with Customers
Revenue	4.5	5.4	14.8	15.7
Other business services - Wholesale and colocation lease revenue
Revenue from Contracts with Customers
Revenue	4.4	5.0	14.1	14.6
Residential subscription | Subscription services
Revenue from Contracts with Customers
Revenue	117.4	132.1	356.9	395.9
Residential subscription | Subscription services | Hurricane Helene
Revenue from Contracts with Customers
Customer credits	0.6		0.6
Residential subscription | HSD
Revenue from Contracts with Customers
Revenue	87.5	90.8	260.1	265.6
Residential subscription | Video
Revenue from Contracts with Customers
Revenue	25.5	36.1	83.1	114.0
Residential subscription | Telephony
Revenue from Contracts with Customers
Revenue	4.4	5.2	13.7	16.3
Business subscription | Subscription services
Revenue from Contracts with Customers
Revenue	28.6	28.2	84.6	84.2
Business subscription | HSD
Revenue from Contracts with Customers
Revenue	20.0	19.0	58.6	56.1
Business subscription | Video
Revenue from Contracts with Customers
Revenue	2.5	2.8	7.5	8.6
Business subscription | Telephony
Revenue from Contracts with Customers
Revenue	$ 6.1	$ 6.4	$ 18.5	$ 19.5