Debt and Receivables Securitization - Additional Information (Detail) - USD ($)						12 Months Ended
	Sep. 26, 2014	Apr. 15, 2014	Aug. 10, 2012	Apr. 27, 2012	Apr. 13, 2010	May 31, 2017	May 31, 2016	May 31, 2015	Oct. 15, 2014
Debt And Receivables Securitization [Line Items]
Remaining borrowing capacity						$ 486,400,000
Interest Rate Swap
Debt And Receivables Securitization [Line Items]
Interest rate swap, interest rate									2.015%
Interest rate swap, start date						Dec. 26, 2014
Interest rate swap, maturity date						Sep. 26, 2019
Line of Credit Facility, Outstanding Borrowing Percentage									60.00%
4.55% Senior Notes due April 15, 2026
Debt And Receivables Securitization [Line Items]
Principal amount		$ 250,000,000
Debt, maturity date						Apr. 15, 2026
Debt, interest rate		4.55%				4.55%	4.55%
Percentage of principal amount debt instrument was sold to the public		99.789%
Yield to maturity		4.573%
Debt discount		$ 528,000				$ 388,000
Debt issuance cost		2,256,000
Settlement of hedge interest		$ (3,081,000)
Unamortized portion of debt issuance costs						$ 1,677,000
4.60% Senior Notes due August 10, 2024
Debt And Receivables Securitization [Line Items]
Principal amount			$ 150,000,000
Debt, maturity date			Aug. 10, 2024			Aug. 10, 2024
Debt, interest rate			4.60%			4.60%	4.60%
Debt issuance cost			$ 80,000
Unamortized portion of debt issuance costs						$ 48,000
6.50% Unsecured Senior Notes due April 15, 2020
Debt And Receivables Securitization [Line Items]
Principal amount					$ 150,000,000
Debt, maturity date						Apr. 15, 2020
Debt, interest rate					6.50%
Yield to maturity					6.515%
Debt discount					$ 165,000	$ 47,000
Debt issuance cost					1,535,000
Settlement of hedge interest					$ (1,358,000)
Unamortized portion of debt issuance costs						421,000
Percentage of principal amount debt instrument was sold to the public					99.89%
Term Loan maturing May 1, 2019
Debt And Receivables Securitization [Line Items]
Term loan credit facility, term				7 years
Borrowings outstanding						$ 1,713,000
Debt, maturity date						May 01, 2019
Debt, interest rate				2.49%
Maximum borrowing capacity				$ 5,880,000
Debt instrument required monthly payments				$ 76,350
Securities Sold under Agreements to Repurchase
Debt And Receivables Securitization [Line Items]
Borrowings outstanding						$ 0
Maximum borrowing capacity						$ 100,000,000
Maturity date						2018-01
Number of days past due trade accounts receivables are ineligible for securitization						90 days
Facility fee						$ 354,000	$ 540,000	$ 723,000
Worthington Aritas
Debt And Receivables Securitization [Line Items]
Term loan credit facility, term	5 years
Borrowings outstanding						$ 28,687,000
Line of credit, variable rate						1.50%
Unsecured Revolving Credit Facility
Debt And Receivables Securitization [Line Items]
Borrowings outstanding						$ 0
Maximum borrowing capacity						$ 500,000,000
Maturity date						2020-04
Unsecured Revolving Credit Facility | Maximum
Debt And Receivables Securitization [Line Items]
Debt maturity period						1 year
Stand-by Letters of Credit
Debt And Receivables Securitization [Line Items]
Letter of credit amount outstanding						$ 15,294,000
Drawn amount of letter of credit outstanding						0
Letter of Credit
Debt And Receivables Securitization [Line Items]
Letter of credit amount outstanding						$ 13,600,000