Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Investments in Affiliates (Details) - USD ($) $ in Millions	12 Months Ended
Investments in Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Credit for adjustment of liability for transportation costs	$ 0.0	$ 0.0	$ 19.3
Combined Metals of Chicago, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage (in hundredths)	40.00%
Delaco Processing, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage (in hundredths)	49.00%
Rockport Roll Shop LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage (in hundredths)	50.00%
Spartan Steel Coating, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage (in hundredths)	48.00%
Difference between carrying amount and underlying equity	$ 7.7
Cost of Products Sold [Member]
Schedule of Equity Method Investments [Line Items]
Share of income (loss) from equity method investments	$ 5.1	$ 6.6	7.0
Transportation Agreement [Member]
Schedule of Equity Method Investments [Line Items]
Credit for adjustment of liability for transportation costs			$ 19.3