Investment In and Advances to Unconsolidated Affiliates - Balance Sheet of Equity Method Investments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Current assets	$ 235.1	$ 221.2
Property and equipment, net	1,059.8	912.5
Other assets, net	21.2	21.1
Assets	2,686.4	2,551.0
Liabilities and Members' Deficit
Current liabilities	424.2	301.2
Long-term debt	1,622.3	1,473.9
Other liabilities	45.8	39.4
Members' deficit	349.8	509.2
Total liabilities and shareholders' equity	2,686.4	2,551.0
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Assets
Current assets	132.8	64.0
Property and equipment, net	267.5	256.1
Other assets, net	244.9	240.1
Assets	645.2	560.2
Liabilities and Members' Deficit
Current liabilities	133.5	73.3
Long-term debt	753.5	745.0
Other liabilities	42.3	20.6
Members' deficit	(284.1)	(278.7)
Total liabilities and shareholders' equity	$ 645.2	$ 560.2