Financial Statements - Additional Information (Detail) (USD $)							0 Months Ended
	Sep. 30, 2014	Aug. 13, 2014	Oct. 10, 2012 2018 Notes [Member]	Aug. 13, 2014 IPO [Member] 2018 Notes [Member]	Sep. 30, 2014 Acofran [Member]	Sep. 30, 2014 Ryerson China [Member]	Aug. 13, 2014 Ryerson Holding [Member] IPO [Member]	Aug. 13, 2014 Ryerson Holding [Member] IPO [Member] 2018 Notes [Member]	Aug. 13, 2014 Ryerson Holding [Member] IPO [Member] Ryerson Credit Facility [Member]
Summary of Accounting and Financial Policies [Line Items]
Parent company percentage owned by affiliates	66.00%
Ownership percentage by parent					50.00%	50.00%
Additional ownership interest through affiliates						50.00%
Common stock shares, issued							11,000,000
Common stock, per share							$ 11
Net Proceeds from initial public offering							$ 112,400,000
Aggregate principal amount of 2018 notes				99,500,000
Debt Instrument Percentage			11.25%					11.25%
Agreement Termination Advisory fee		25,000,000					25,000,000
Payments related to transaction fees, expenses and premiums on offering							12,600,000
Additional amount borrowed									24,700,000
Amended and restated credit facility agreement									$ 1,350,000,000