Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 17.9	$ (12.7)	$ 14.8	$ (20.5)
Other comprehensive income (loss), net of income tax
Unrealized gain (loss) on derivatives, net of income tax provision of $0.0, $0.0, $0.0 and $0.0, respectively	(0.2)	0.1	(0.2)	0.1
Employee pension and postretirement benefit income (expense), net of income tax benefit of $0.0, $0.3, $0.0 and $0.0, respectively	(1.2)	0.6	(1.8)	1.8
Foreign currency translation adjustments, net of income tax benefit (provision) of $(0.5), $(1.1), $2.7 and $(3.8), respectively		8.6	(10.0)	(5.0)
Total other comprehensive income (loss), net of income tax	(1.4)	9.3	(12.0)	(3.1)
Comprehensive income (loss)	$ 16.5	$ (3.4)	$ 2.8	$ (23.6)