Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 310.3	$ 541.0
Cost of sales	257.2	400.1
Gross margin	53.1	140.9
Selling, general and administrative expenses	39.6	46.5
Research and technology expenses	11.6	14.0
Other operating expense	12.1	14.7
Operating income	(10.2)	65.7
Interest expense, net	10.3	12.0
(Loss) income before income taxes, and equity in earnings from affiliated companies	(20.5)	53.7
Income tax (benefit) expense	(7.5)	11.8
(Loss) income before equity in earnings from affiliated companies	(13.0)	41.9
Equity in (losses) earnings from affiliated companies	(1.0)	0.5
Net (loss) income	$ (14.0)	$ 42.4
Basic net (loss) income per common share	$ (0.17)	$ 0.51
Diluted net (loss) income per common share	$ (0.17)	0.50
Dividends per share		$ 0.17
Weighted-average common shares:
Basic	84.0	83.7
Diluted	84.0	84.3