Equity Method Investments (Income Statement) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
Total revenues	$ 473.0	$ 589.4	$ 774.6
Gross (loss) profit	(12.8)	(13.2)	(11.3)
Operating and non-operating expense	22.3	22.2	25.6
Net loss	$ (35.1)	$ (35.4)	$ (36.9)