Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 491.3	$ 522.6	$ 970.1	$ 1,020.3
Cost of sales	351.4	372.3	696.1	727.0
Gross margin	139.9	150.3	274.0	293.3
Selling, general and administrative expenses	38.1	38.6	81.0	86.0
Research and technology expenses	12.1	11.6	24.7	23.3
Operating income	89.7	100.1	168.3	184.0
Interest expense, net	6.8	5.7	13.0	11.3
Non-operating expense		0.4		0.4
Income before income taxes, and equity in earnings from affiliated companies	82.9	94.0	155.3	172.3
Provision for income taxes	22.1	28.7	30.7	51.4
Income before equity in earnings from affiliated companies	60.8	65.3	124.6	120.9
Equity in earnings from affiliated companies	0.8	0.8	1.6	1.2
Net income	$ 61.6	$ 66.1	$ 126.2	$ 122.1
Basic net income per common share	$ 0.68	$ 0.71	$ 1.39	$ 1.31
Diluted net income per common share	0.67	0.70	1.37	1.29
Dividends per share	$ 0.11	$ 0.10	$ 0.22	$ 0.21
Weighted-average common shares:
Basic	90.7	93.1	91.1	93.3
Diluted	92.0	94.6	92.4	94.7