Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 540.5	$ 491.5	$ 1,628.1	$ 1,461.6
Cost of sales	397.5	355.9	1,197.7	1,052.0
Gross margin	143.0	135.6	430.4	409.6
Selling, general and administrative expenses	32.6	34.7	114.3	115.7
Research and technology expenses	13.9	11.8	40.7	36.5
Operating income	96.5	89.1	275.4	257.4
Interest expense, net	10.6	7.0	27.3	20.0
Income before income taxes, and equity in earnings from affiliated companies	85.9	82.1	248.1	237.4
Provision for income taxes	7.8	13.6	41.9	44.3
Income before equity in earnings from affiliated companies	78.1	68.5	206.2	193.1
Equity in earnings from affiliated companies	2.0	1.2	4.3	2.8
Net income	$ 80.1	$ 69.7	$ 210.5	$ 195.9
Basic net income per common share	$ 0.92	$ 0.77	$ 2.37	$ 2.16
Diluted net income per common share	0.91	0.76	2.35	2.13
Dividends per share	$ 0.15	$ 0.125	$ 0.40	$ 0.345
Weighted-average common shares:
Basic	87.0	90.1	88.6	90.7
Diluted	88.1	91.4	89.7	92.1