Debt and Receivables Securitization - Additional Information (Detail) (USD $)				3 Months Ended					1 Months Ended
	Aug. 31, 2012 Unsecured Revolving Credit Facility	Aug. 31, 2012 Line of Credit	Aug. 31, 2012 Worthington Nitin Cylinders Limited	Aug. 31, 2012 Maximum Line of Credit	Aug. 31, 2012 Financial Stand-By Letters Of Credit	Aug. 31, 2012 Accounts Receivable Facilities Day	Feb. 29, 2012 Accounts Receivable Facilities	Nov. 30, 2011 Accounts Receivable Facilities	Aug. 10, 2012 2024 Notes
Debt And Receivables Securitization [Line Items]
Principal amount									$ 150,000,000
Debt maturity date									Aug. 10, 2024
Debt, interest rate									4.60%
Maximum borrowing capacity	425,000,000		9,500,000			150,000,000	150,000,000	100,000,000
Maturity date	2017-05		2012-11			2013-01
Borrowings outstanding	30,435,000		5,799,000			15,000,000
Outstanding stand-by letters of credit amount for third-party beneficiaries					10,982,000
Remaining borrowing capacity		$ 383,583,000
Applicable variable rate	1.28%		3.25%
Debt maturity period				1 year
Number of days past due trade accounts receivables are ineligible for securitization						90