Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 9.7	$ 0.5	$ (0.3)	$ (35.5)
Other comprehensive income (loss), net of tax
Unrealized income (expense) on derivatives, net of income tax provision of $0.0, $0.0, $0.0 and $0.0, respectively	(3.3)	0.1	(3.4)	0.6
Employee pension and postretirement benefits, net of income tax provision of $(0.1), $0.4, $0.0 and $0.8, respectively	0.7	0.5	1.3	1.1
Foreign currency translation adjustments	(26.8)	23.1	(15.2)	33.2
Total other comprehensive income (loss), net of tax	(29.4)	23.7	(17.3)	34.9
Comprehensive income (loss)	$ (19.7)	$ 24.2	$ (17.6)	$ (0.6)