Related Parties - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transactions [Abstract]
Annual related party monitoring fee maximum				$ 5.0
Payment of monitoring fee				5.0	5.0	5.0
Distributions to Ryerson Holding	$ 344.9	$ 6.6	$ 35.0	$ 6.6	$ 379.9