Condensed Consolidated Statements of Comprehensive Income (Loss) - 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)	$ 2.2	$ (1.0)	$ (11.8)	$ 41.4
Currency translation adjustments	4.2	8.8	(7.8)	(16.0)
Net unrealized pension and other benefit actuarial (losses) gains and prior service credits (net of tax)	(0.2)	(0.1)	(1.9)	0.8
Net unrealized gains (losses) on financial instruments (net of tax)	1.5	8.6	(3.9)	(4.1)
Total other comprehensive income (loss)	5.5	17.3	(13.6)	(19.3)
Comprehensive income (loss)	$ 7.7	$ 16.3	$ (25.4)	$ 22.1