Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 46.6	$ (67.1)	$ 9.4
Other comprehensive income (loss), net of income tax:
Net unrealized gains (losses) on derivatives, net of income tax provision of $0.0, $0.0 and $0.0, respectively	0.3	(0.4)	0.4
Employee pension and postretirement benefit income (loss), net of income tax benefit of $0.2, $1.4 and $4.2, respectively	(3.7)	8.9	6.7
Foreign currency translation adjustments	(1.0)	(27.7)	58.4
Total other comprehensive income (loss), net of income tax	(4.4)	(19.2)	65.5
Comprehensive income (loss)	$ 42.2	$ (86.3)	$ 74.9