Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 2,355.7	$ 2,189.1	$ 1,973.3
Cost of sales	1,715.3	1,608.3	1,421.5
Gross margin	640.4	580.8	551.8
Selling, general and administrative expenses	158.7	146.0	151.8
Research and technology expenses	56.5	55.9	49.4
Other operating expense		7.7
Operating income	425.2	371.2	350.6
Interest expense, net	45.5	37.7	27.4
Income before income taxes, and equity in earnings of affiliated companies	379.7	333.5	323.2
Provision for income taxes	76.8	62.5	42.5
Income before equity in earnings of affiliated companies	302.9	271.0	280.7
Equity in earnings from affiliated companies	3.7	5.6	3.3
Net income	$ 306.6	$ 276.6	$ 284.0
Basic net income per common share:	$ 3.61	$ 3.15	$ 3.13
Diluted net income per common share:	$ 3.57	$ 3.11	$ 3.09
Weighted-average common shares:
Basic	84.9	87.9	90.6
Diluted	85.8	89.0	91.9