Assets Measured at Fair Value on Non-recurring Basis (Parenthetical) (Detail) (USD $)	3 Months Ended		3 Months Ended						3 Months Ended
	Aug. 31, 2013	May 31, 2013	May 31, 2013 Worthington Nitin Cylinders Limited	Aug. 31, 2013 Long-lived assets held and used		May 31, 2013 Long-lived assets held and used		May 31, 2013 Long-lived assets held and used Worthington Nitin Cylinders Limited	May 31, 2013 Noncontrolling Interest Worthington Nitin Cylinders Limited	Aug. 31, 2013 Joint Venture Transactions Worthington Nitin Cylinders Limited	May 31, 2013 Joint Venture Transactions Worthington Nitin Cylinders Limited
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset measured at fair value on nonrecurring basis	$ 11,827,000	$ 6,856,000		$ 11,827,000	[1]	$ 6,856,000	[2]	$ 6,856,000
Impairment of long-lived assets	$ 4,641,000		$ 4,968,000						$ 1,987,000
Percent of controlling interest by the company										60.00%	60.00%

[1] During the first quarter of fiscal 2014, we determined that certain indicators of impairment were present with regard to certain non-core Steel Processing assets. Recoverability of the identified asset group was tested using future cash flow projections based on management's estimate of market conditions. The sum of these undiscounted future cash flows was less than the net book value of the asset group. The net book value was also determined to be in excess of fair value and, accordingly, the asset group was written down to its fair value of $11,827,000, resulting in an impairment charge of $4,641,000. This impairment charge was recorded within impairment of long-lived assets in our consolidated statement of earnings. Fair value was determined based on market prices for similar assets.

[2] During the fourth quarter of fiscal 2013, the long-lived assets of our 60%-owned consolidated joint venture in India, WNCL, were written down to their fair value of $6,856,000, resulting in an impairment charge of $4,968,000. This impairment loss was recorded within impairment of long-lived assets in our consolidated statement of earnings. The portion of this impairment loss attributable to the noncontrolling interest, or $1,987,000, is recorded within net earnings attributable to noncontrolling interest in our consolidated statement of earnings. Fair value was determined based on market prices for similar assets.