Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Current assets	$ 1,241.9	$ 1,254.3
Property, plant and equipment net of accumulated depreciation	452.7	483.4
Other noncurrent assets	223.4	226.5
Total assets	1,918.0	1,964.2
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	461.1	456.0
Noncurrent liabilities	1,600.1	1,788.7
Redeemable noncontrolling interest	1.3	1.7
Ryerson Inc. stockholders' equity	(142.0)	(284.9)
Noncontrolling interest	(2.5)	2.7
Total Liabilities and Equity	1,918.0	1,964.2
Parent [Member]
ASSETS
Current assets	3.5	381.7
Other noncurrent assets	1,113.0	944.2
Total assets	1,116.5	1,325.9
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	259.3	16.5
Noncurrent liabilities	999.2	1,594.3
Ryerson Inc. stockholders' equity	(142.0)	(284.9)
Total Liabilities and Equity	1,116.5	1,325.9
Joseph T. Ryerson [Member]
ASSETS
Current assets	1,173.7	2,215.9
Property, plant and equipment net of accumulated depreciation	387.8	410.8
Other noncurrent assets	870.6	319.2
Total assets	2,432.1	2,945.9
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	239.7	254.3
Noncurrent liabilities	1,200.0	1,872.2
Ryerson Inc. stockholders' equity	992.4	819.4
Total Liabilities and Equity	2,432.1	2,945.9
Guarantor Subsidiaries [Member]
ASSETS
Current assets	113.0	63.0
Property, plant and equipment net of accumulated depreciation	3.1	3.1
Other noncurrent assets	321.8	1,818.6
Total assets	437.9	1,884.7
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	135.0	1,738.3
Noncurrent liabilities	5.3	0.8
Ryerson Inc. stockholders' equity	297.6	145.6
Total Liabilities and Equity	437.9	1,884.7
Non-Guarantor Subsidiaries [Member]
ASSETS
Current assets	235.4	214.5
Property, plant and equipment net of accumulated depreciation	61.8	69.5
Other noncurrent assets	5.8	14.4
Total assets	303.0	298.4
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	110.8	67.7
Noncurrent liabilities	27.7	32.8
Redeemable noncontrolling interest	1.3	1.7
Ryerson Inc. stockholders' equity	165.7	193.5
Noncontrolling interest	(2.5)	2.7
Total Liabilities and Equity	303.0	298.4
Eliminations [Member]
ASSETS
Current assets	(283.7)	(1,620.8)
Other noncurrent assets	(2,087.8)	(2,869.9)
Total assets	(2,371.5)	(4,490.7)
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	(283.7)	(1,620.8)
Noncurrent liabilities	(632.1)	(1,711.4)
Ryerson Inc. stockholders' equity	(1,455.7)	(1,158.5)
Total Liabilities and Equity	$ (2,371.5)	$ (4,490.7)