Revision of Previously Issued Financial Statements - Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Reclassification [Line Items]
Net sales	$ 549.8	$ 545.3	$ 1,589.4	$ 1,598.3
Cost of sales (exclusive of items shown separately below)	459.3	446.5	1,354.3	1,310.6
Selling, general and administrative expense	5.6	5.2	23.4	27.8
Depreciation and amortization	13.8	13.5	42.0	44.4
Other expense, net	1.9	8.7	1.5	24.0
Total operating costs and expenses	496.5	473.9	1,465.2	1,406.8
Operating income	53.3	71.4	124.2	191.5
Total non-operating expense, net	25.9	14.1	34.8	49.5
Income before income taxes	27.4	57.3	89.4	142.0
Income tax provision	13.7	14.8	31.5	36.4	$ 2.9
Net income	$ 13.7	$ 42.5	$ 57.9	$ 105.6
Basic EPS (in dollars per share)	$ 0.17	$ 0.53	$ 0.72	$ 1.33
Diluted EPS (in dollars per share)	$ 0.17	$ 0.51	$ 0.70	$ 1.29
Weighted average shares of common stock outstanding, basic (in shares)	80.3	79.9	80.3	79.0
Weighted average shares of common stock outstanding, diluted (in shares)	81.2	82.3	84.3	81.5
Previously Reported
Reclassification [Line Items]
Net sales		$ 545.3		$ 1,598.3
Cost of sales (exclusive of items shown separately below)		446.5		1,310.6
Selling, general and administrative expense		5.2		27.8
Depreciation and amortization		13.5		44.4
Other expense, net		8.7		24.0
Total operating costs and expenses		473.9		1,406.8
Operating income		71.4		191.5
Total non-operating expense, net		14.1		49.5
Income before income taxes		57.3		142.0
Income tax provision		14.7		36.3
Net income		$ 42.6		$ 105.7
Basic EPS (in dollars per share)		$ 0.53		$ 1.33
Diluted EPS (in dollars per share)		$ 0.52		$ 1.29
Weighted average shares of common stock outstanding, basic (in shares)		79.9		79.0
Weighted average shares of common stock outstanding, diluted (in shares)		82.3		81.5
Adjustments
Reclassification [Line Items]
Net sales		$ 0.0		$ 0.0
Cost of sales (exclusive of items shown separately below)		0.0		0.0
Selling, general and administrative expense		0.0		0.0
Depreciation and amortization		0.0		0.0
Other expense, net		0.0		0.0
Total operating costs and expenses		0.0		0.0
Operating income		0.0		0.0
Total non-operating expense, net		0.0		0.0
Income before income taxes		0.0		0.0
Income tax provision		0.1		0.1
Net income		$ (0.1)		$ (0.1)
Basic EPS (in dollars per share)		$ 0		$ 0
Diluted EPS (in dollars per share)		$ (0.01)		$ 0
Weighted average shares of common stock outstanding, basic (in shares)		0.0		0.0
Weighted average shares of common stock outstanding, diluted (in shares)		0.0		0.0