Condensed Consolidating Guarantor Financial Statements - Condensed Consolidating Balance Sheet (Unaudited) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents	$ 82.5	$ 74.0	$ 75.7	$ 70.8
Receivables less provision for allowances, claims and doubtful accounts	466.4	385.4
Inventories	723.0	733.0
Other current assets	39.6	49.5
Total current assets	1,311.5	1,241.9
Property, plant and equipment net of accumulated depreciation	443.9	452.7
Other noncurrent assets	213.1	223.4
Total assets	1,968.5	1,918.0
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	319.3	207.2
Deferred income taxes	119.0	121.0
Other current liabilities	136.2	253.9
Total current liabilities	574.5	461.1
Long-term debt	1,225.0	1,262.5
Deferred employee benefits	289.8	320.8
Taxes and other credits	22.4	16.8
Total liabilities	2,111.7	2,061.2
Redeemable noncontrolling interest	1.2	1.3
Ryerson Inc. stockholders' equity	(140.1)	(142.0)
Noncontrolling interest	(4.3)	(2.5)
Total liabilities and equity	1,968.5	1,918.0
Parent [Member]
Assets
Cash and cash equivalents	0.1		5.0	0.2
Receivables less provision for allowances, claims and doubtful accounts	3.8	3.5
Other current assets	0.4
Total current assets	4.3	3.5
Investments in subsidiaries	1,017.9	1,005.7
Other noncurrent assets	114.6	107.3
Total assets	1,136.8	1,116.5
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable		(0.2)
Intercompany payable	251.4	247.6
Deferred income taxes	1.3
Other current liabilities	3.0	11.9
Total current liabilities	255.7	259.3
Long-term debt	325.0	362.5
Long-term debt - intercompany	689.6	629.9
Deferred employee benefits	0.7	0.6
Taxes and other credits	5.9	6.2
Total liabilities	1,276.9	1,258.5
Ryerson Inc. stockholders' equity	(140.1)	(142.0)
Total liabilities and equity	1,136.8	1,116.5
Joseph T. Ryerson [Member]
Assets
Cash and cash equivalents	8.8	7.8	10.6	15.3
Receivables less provision for allowances, claims and doubtful accounts	359.0	290.4
Inventories	622.1	637.1
Intercompany receivable	154.8	227.0
Other current assets	9.0	11.4
Total current assets	1,153.7	1,173.7
Investments in subsidiaries	434.3	416.0
Intercompany notes receivable	446.8	406.1
Property, plant and equipment net of accumulated depreciation	382.5	387.8
Other noncurrent assets	37.7	48.5
Total assets	2,455.0	2,432.1
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	53.4	35.1
Deferred income taxes	119.1
Other current liabilities	89.1	204.6
Total current liabilities	261.6	239.7
Long-term debt	900.0	900.0
Deferred employee benefits	264.3	294.4
Taxes and other credits	11.4	5.6
Total liabilities	1,437.3	1,439.7
Ryerson Inc. stockholders' equity	1,017.7	992.4
Total liabilities and equity	2,455.0	2,432.1
Guarantor [Member]
Assets
Cash and cash equivalents	18.4	2.4	3.1	1.9
Receivables less provision for allowances, claims and doubtful accounts	12.5	8.8
Inventories	24.8	25.8
Intercompany receivable	131.3	55.2
Other current assets	15.5	20.8
Total current assets	202.5	113.0
Investments in subsidiaries	34.1	34.0
Intercompany notes receivable	242.8	223.8
Property, plant and equipment net of accumulated depreciation	3.4	3.1
Other noncurrent assets	62.4	64.0
Total assets	545.2	437.9
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	229.1	132.8
Deferred income taxes	0.5
Other current liabilities	4.2	2.2
Total current liabilities	233.8	135.0
Taxes and other credits	10.4	5.3
Total liabilities	244.2	140.3
Ryerson Inc. stockholders' equity	301.0	297.6
Total liabilities and equity	545.2	437.9
Non-Guarantor [Member]
Assets
Cash and cash equivalents	55.2	63.8	57.0	53.4
Receivables less provision for allowances, claims and doubtful accounts	91.1	82.7
Inventories	76.1	70.1
Other current assets	16.4	18.8
Total current assets	238.8	235.4
Property, plant and equipment net of accumulated depreciation	58.0	61.8
Other noncurrent assets	5.7	5.8
Total assets	302.5	303.0
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	36.7	39.1
Intercompany payable	34.8	35.0
Other current liabilities	39.7	36.7
Total current liabilities	111.2	110.8
Deferred employee benefits	24.8	25.8
Taxes and other credits	2.0	1.9
Total liabilities	138.0	138.5
Redeemable noncontrolling interest	1.2	1.3
Ryerson Inc. stockholders' equity	167.6	165.7
Noncontrolling interest	(4.3)	(2.5)
Total liabilities and equity	302.5	303.0
Eliminations [Member]
Assets
Intercompany receivable	(286.1)	(282.2)
Other current assets	(1.7)	(1.5)
Total current assets	(287.8)	(283.7)
Investments in subsidiaries	(1,486.3)	(1,455.7)
Intercompany notes receivable	(689.6)	(629.9)
Other noncurrent assets	(7.3)	(2.2)
Total assets	(2,471.0)	(2,371.5)
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	0.1	0.4
Intercompany payable	(286.2)	(282.6)
Deferred income taxes	(1.9)
Other current liabilities	0.2	(1.5)
Total current liabilities	(287.8)	(283.7)
Long-term debt - intercompany	(689.6)	(629.9)
Taxes and other credits	(7.3)	(2.2)
Total liabilities	(984.7)	(915.8)
Ryerson Inc. stockholders' equity	(1,486.3)	(1,455.7)
Total liabilities and equity	$ (2,471.0)	$ (2,371.5)