Investment in and Advances to Unconsolidated Affiliates - Affiliate Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Investments in and Advances to Affiliates [Line Items]
Current assets	$ 532.6	$ 235.1
Property and equipment, net	1,057.6	1,082.1
Other assets, net	20.8	21.2
Total assets	2,970.6	2,686.4
Current liabilities	369.5	424.2
Other liabilities	55.7	45.8
Members' deficit	309.5	349.8
Total liabilities and shareholders' equity	2,970.6	2,686.4
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Investments in and Advances to Affiliates [Line Items]
Current assets	86.3	132.8
Property and equipment, net	268.1	267.5
Other assets, net	266.3	244.9
Total assets	620.7	645.2
Current liabilities	78.0	133.5
Long-term debt	772.0	753.5
Other liabilities	32.7	42.3
Members' deficit	(262.0)	(284.1)
Total liabilities and shareholders' equity	$ 620.7	$ 645.2