Revenue - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Payment terms for customers, lower range	30 days
Payment term for customers, upper range	120 days
Total	$ 138.0
Unearned revenue and customer deposits	56.3	$ 68.9
Other Current Liabilities [Member]
Disaggregation Of Revenue [Line Items]
Unearned revenue and customer deposits	1.7	1.6
Other Noncurrent Liabilities [Member]
Disaggregation Of Revenue [Line Items]
Contract liabilities, recognized, noncurrent	$ 58.1	$ 26.2
Contract Signed in Successor Period [Member]
Disaggregation Of Revenue [Line Items]
Indefeasible right of use of contract term	20 years
Revenue, Remaining Performance Obligation, Percentage	75.00%
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