Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 547.5	$ 491.3	$ 1,087.6	$ 970.1
Cost of sales	402.7	351.4	800.2	696.1
Gross margin	144.8	139.9	287.4	274.0
Selling, general and administrative expenses	35.3	38.1	81.7	81.0
Research and technology expenses	13.0	12.1	26.8	24.7
Operating income	96.5	89.7	178.9	168.3
Interest expense, net	8.7	6.8	16.7	13.0
Income before income taxes, and equity in earnings from affiliated companies	87.8	82.9	162.2	155.3
Provision for income taxes	20.0	22.1	34.1	30.7
Income before equity in earnings from affiliated companies	67.8	60.8	128.1	124.6
Equity in earnings from affiliated companies	1.0	0.8	2.3	1.6
Net income	$ 68.8	$ 61.6	$ 130.4	$ 126.2
Basic net income per common share	$ 0.77	$ 0.68	$ 1.45	$ 1.39
Diluted net income per common share	0.76	0.67	1.44	1.37
Dividends per share	$ 0.125	$ 0.11	$ 0.25	$ 0.22
Weighted-average common shares:
Basic	88.8	90.7	89.4	91.1
Diluted	89.9	92.0	90.5	92.4