Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2025	Sep. 30, 2024	Dec. 31, 2024
Disaggregation Of Revenue [Line Items]
Payment terms for customers, lower range	30 days
Payment term for customers, upper range	120 days
Total	$ 211.0
Unearned revenue and customer deposits	51.9		$ 50.6
Broadband Expansion in Southwest Ohio [Member]
Disaggregation Of Revenue [Line Items]
Contract	50.0
Other Current Liabilities [Member]
Disaggregation Of Revenue [Line Items]
Unearned revenue and customer deposits	4.3		4.3
Other Noncurrent Liabilities [Member]
Disaggregation Of Revenue [Line Items]
Contract liabilities, recognized, noncurrent	$ 88.3		$ 89.4
Minimum [Member]
Disaggregation Of Revenue [Line Items]
Customer contract term	1 year
SEA-US contract term	15 years
Indefeasible right of use of contract term	15 years
Maximum [Member]
Disaggregation Of Revenue [Line Items]
Customer contract term	5 years
SEA-US contract term	25 years
Indefeasible right of use of contract term	25 years
Indefeasible Right of Use, Maximum, in Years		30 years