Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales	$ 491.5	$ 500.5	$ 1,461.6	$ 1,520.8
Cost of sales	355.9	364.8	1,052.0	1,091.8
Gross margin	135.6	135.7	409.6	429.0
Selling, general and administrative expenses	34.7	35.1	115.7	121.1
Research and technology expenses	11.8	11.5	36.5	34.8
Operating income	89.1	89.1	257.4	273.1
Interest expense, net	7.0	5.5	20.0	16.8
Non-operating expense				0.4
Income before income taxes, and equity in earnings from affiliated companies	82.1	83.6	237.4	255.9
Provision for income taxes	13.6	16.1	44.3	67.5
Income before equity in earnings from affiliated companies	68.5	67.5	193.1	188.4
Equity in earnings from affiliated companies	1.2	0.7	2.8	1.9
Net income	$ 69.7	$ 68.2	$ 195.9	$ 190.3
Basic net income per common share	$ 0.77	$ 0.74	$ 2.16	$ 2.04
Diluted net income per common share	0.76	0.72	2.13	2.01
Dividends per share	$ 0.125	$ 0.11	$ 0.345	$ 0.32
Weighted-average common shares:
Basic	90.1	92.7	90.7	93.1
Diluted	91.4	94.1	92.1	94.6