Investment in and Advances to Unconsolidated Affiliates - Affiliate Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments in and Advances to Affiliates [Line Items]
Current assets	$ 346.8	$ 235.1
Property and equipment, net	1,068.7	1,082.1
Other assets, net	21.7	21.2
Total assets	2,787.1	2,686.4
Current liabilities	305.2	424.2
Other liabilities	48.2	45.8
Members' deficit	201.4	349.8
Total liabilities and members' deficit	2,787.1	2,686.4
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Investments in and Advances to Affiliates [Line Items]
Current assets	87.7	132.8
Property and equipment, net	265.7	267.5
Other assets, net	246.5	244.9
Total assets	599.9	645.2
Current liabilities	122.1	133.5
Long-term debt	722.0	753.5
Other liabilities	35.6	42.3
Members' deficit	(279.8)	(284.1)
Total liabilities and members' deficit	$ 599.9	$ 645.2