Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 178.8	$ 11.3	$ 211.6	$ 6.6
Other comprehensive income:
Foreign currency translation	(0.5)	2.1	(2.8)	6.9
Total comprehensive income	$ 178.3	$ 13.4	$ 208.8	$ 13.5