Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net sales	$ 405.3	$ 356.9
Operating costs and expenses:
Cost of sales (exclusive of items shown separately below)	352.7	309.7
Selling, general and administrative	18.5	11.6
Depreciation and amortization	16.3	15.1
Other expense, net	1.7	0.7
Total operating costs and expenses	389.2	337.1
Operating income	16.1	19.8
Loss on debt	0.0	0.3
Non-operating (income) expense:
Interest income	(0.5)	(0.2)
Interest expense	7.4	11.1
Total non-operating expense, net	6.9	11.2
Income before income taxes	9.2	8.6
Income tax provision	3.3	3.5
Net income	$ 5.9	$ 5.1
Earnings Per Share of Common Stock
Net income per share (in USD per share)	$ 0.08	$ 0.08
Weighted average shares of common stock outstanding, basic (in shares)	72.3	63.0
Weighted average shares of common stock outstanding, diluted (in shares)	72.3	63.1