Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_DebtInstrumentMaturityDateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Subsequent Event - Additional Information (Detail) (Ryerson Secured Credit Facility)	3 Months Ended	12 Months Ended	1 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Apr. 03, 2013 Subsequent Event	Apr. 03, 2013 Subsequent Event Minimum	Apr. 03, 2013 Subsequent Event Maximum	Apr. 03, 2013 Subsequent Event Scenario One	Apr. 03, 2013 Subsequent Event Scenario Two
Subsequent Event [Line Items]
Credit facility amendement, description			Extend the maturity date to the earlier of (a) April 3, 2018 or (b) August 16, 2017 (60 days prior to the scheduled maturity date of the 2017 Notes), if the 2017 Notes are then outstanding.
Credit facility amendement, maturity date	Mar. 14, 2016	Mar. 14, 2016				Apr. 03, 2018	Aug. 16, 2017
Interest rate reduction, basis points				0.25%	0.50%
Commitment fee reduction, basis points			0.125%