Consolidated Statement of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net sales	$ 694.1	$ 582.4	$ 1,305.0	$ 1,087.0
Operating costs and expenses:
Cost of sales	485.7	443.1	940.7	858.6
Depreciation and amortization	29.6	28.5	60.2	56.4
Selling and administrative	47.0	46.5	95.6	88.8
(Gain) loss on sale or impairment of long-lived assets, net	(3.1)	0.7	(2.5)	0.7
Other operating credits and charges, net	2.0	11.4	5.4	11.4
Total operating costs and expenses	561.2	530.2	1,099.4	1,015.9
Income from operations	132.9	52.2	205.6	71.1
Non-operating income (expense):
Interest expense, net of capitalized interest	(4.9)	(9.3)	(9.9)	(17.3)
Investment income	2.3	2.1	4.3	3.9
Other non-operating items	(1.5)	1.4	(1.8)	1.9
Total non-operating income (expense)	(4.1)	(5.8)	(7.4)	(11.5)
Income before taxes and equity in income of unconsolidated affiliates	128.8	46.4	198.2	59.6
Provision for income taxes	36.0	16.2	51.5	20.6
Equity in income of unconsolidated affiliates	(1.7)	(1.5)	(2.8)	(3.0)
Net income	$ 94.5	$ 31.7	$ 149.5	$ 42.0
Net income per share of common stock:
Net income per share - basic	$ 0.65	$ 0.22	$ 1.04	$ 0.29
Net income per share - diluted	$ 0.65	$ 0.22	$ 1.02	$ 0.29
Weighted average shares of stock outstanding - basic	144.5	143.4	144.3	143.1
Weighted average shares of stock outstanding - diluted	146.2	145.2	146.0	145.1