Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 540.1	$ 478.8
Cost of sales	397.5	344.7
Gross margin	142.6	134.1
Selling, general and administrative expenses	46.4	42.9
Research and technology expenses	13.8	12.6
Operating income	82.4	78.6
Interest expense, net	8.0	6.2
Income before income taxes, and equity in earnings from affiliated companies	74.4	72.4
Provision for income taxes	14.1	8.6
Income before equity in earnings from affiliated companies	60.3	63.8
Equity in earnings from affiliated companies	1.3	0.8
Net income	$ 61.6	$ 64.6
Basic net income per common share	$ 0.68	$ 0.71
Diluted net income per common share	0.68	0.70
Dividends per share	$ 0.125	$ 0.11
Weighted-average common shares:
Basic	90.0	91.4
Diluted	91.2	92.9