Debt and Receivables Securitization - Additional Information (Detail) (USD $)			12 Months Ended		12 Months Ended		12 Months Ended				12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	0 Months Ended	12 Months Ended				12 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014 Unsecured Revolving Credit Facility	May 31, 2014 Line of Credit	May 31, 2014 Line of Credit Maximum	May 31, 2014 Worthington Aritas	May 31, 2014 Worthington Nitin Cylinders Limited	May 31, 2014 Cash Flow Hedges Interest Rate Contracts	May 31, 2014 Cash Flow Hedges Interest Rate Contracts Six-month LIBOR rate	May 31, 2014 Financial Stand-By Letters Of Credit	May 31, 2014 2014 Notes	Aug. 10, 2012 4.60% senior notes due August 10, 2024	May 31, 2014 4.60% senior notes due August 10, 2024	Apr. 13, 2014 Unsecured Senior Notes, Four Point Five Five Percent, Due April Fifteen Twenty Twenty Six	May 31, 2014 Unsecured Senior Notes, Four Point Five Five Percent, Due April Fifteen Twenty Twenty Six	Apr. 13, 2010 6.50% Unsecured Senior Notes due April 15, 2020	Dec. 29, 2011 Industrial revenue bonds due April 2019	May 31, 2014 Industrial revenue bonds due April 2019	Dec. 29, 2011 Industrial revenue bonds due April 2019	Dec. 29, 2011 Industrial revenue bonds due April 2019 Maximum	Dec. 29, 2011 Industrial revenue bonds due April 2019 Minimum	May 31, 2014 Securities Sold under Agreements to Repurchase	Mar. 31, 2013 Securities Sold under Agreements to Repurchase	Mar. 31, 2012 Securities Sold under Agreements to Repurchase
Debt And Receivables Securitization [Line Items]
Borrowings outstanding	$ 0					$ 4,437,000	$ 5,925,000															$ 0
Debt, Interest rate						5.60%
Line of Credit Facility, Maximum Borrowing Capacity	11,732,000		425,000,000				9,500,000															100,000,000
Maturity date			2017-05				2014-11															2015-01
Applicable variable rate							7.52%
Number of days past due trade accounts receivables are ineligible for securitization																						90 days
Facility fee																						652,000	983,000	1,232,000
Debt maturity period					1 year
Average variable rate				1.20%
Outstanding stand-by letters of credit amount for third-party beneficiaries										14,332,000
Remaining borrowing capacity	413,268,000
Debt borrowings outstanding	655,963,000	407,328,000									100,000,000								2,024,000
Debt maturity date											Dec. 17, 2014	Aug. 10, 2024	Aug. 10, 2024	Apr. 15, 2026	Apr. 15, 2026	Apr. 15, 2020
Basis spread on variable rate											0.80%
Notional Amount								100,000,000	100,000,000
Interest rate swap interest rate									4.46%
Debt instrument effective interest rate percentage after interest rate swap											5.26%
Principal amount												150,000,000		250,000,000		150,000,000
Debt interest rate												4.60%	4.60%	4.55%	4.55%	6.50%				5.00%	2.75%
Percentage of principal amount debt instrument was sold to the public														99.789%
Yield to maturity														4.573%		6.515%
Debt discount														528,000		165,000
Debt issuance cost														2,256,000		1,535,000
Settlement of hedge interest														3,081,000		1,358,000
Percentage of principal amount debt instrument was sold to the public																99.89%
Debt instrument maturity month and year																	2019-04	2019-04
Debt instrument required monthly payments																	$ 31,000