Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012 item	Dec. 31, 2011
Summary of Significant Accounting Policies
Minimum number of locations in which company operates metal service network	240
Number of states in which the company operates metal service center network	38
Number of countries in which the company operates metal service center network	10
Minimum number of metal products distributes by the company	100,000
Fair Values of Financial Instruments
Carrying value, before deducting unamortized discount or premiums	$ 1,208.9	$ 1,332.8
Carrying value	1,208.9
Goodwill Policy
Number of operating segments	1
Number of reportable segments	1
Tradename
Impairment loss related to trade name intangible assets	2.5
Senior Unsecured Notes - Publicly Traded
Fair Values of Financial Instruments
Carrying value, before deducting unamortized discount or premiums	600.0
Fair value	675.1	638.1
Carrying value	$ 598.5	$ 598.4

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Represents the minimum number of metal products distributed by entity.

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The minimum number of locations the entity operates in as of the balance sheet date.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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No definition available.

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The number of reportable segments of the entity.

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Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an indefinite-lived intangible asset, other than goodwill, to fair value.

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Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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The number of countries in which the entity operates as of balance sheet date.

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The number of states the entity operates in as of the balance sheet date.

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