Investment in and Advances to Unconsolidated Affiliates Affiliate Income Statement (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Affiliate Income Statement [Abstract]
Net revenue	$ 114.5	$ 109.4	$ 216.1	$ 212.7
Operating and SG&A expense	84.4	83.8	163.3	165.5
Depreciation and amortization	6.6	5.1	13.1	10.9
Total operating expense	91.0	88.9	176.4	176.4
Operating income	23.5	20.5	39.7	36.3
Interest and other expense, net	(2.6)	(2.7)	(4.9)	(5.3)
Net income	$ 20.9	$ 17.8	$ 34.8	$ 31.0