Investments In Unconsolidated Affiliates (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Aug. 31, 2011	May 31, 2011
Distributions from unconsolidated affiliates	$ 19,628,000
Joint Venture Transactions [Member] | Arti Flex [Member]
Percent of interest by unconsolidated affiliates	50.00%
Joint Venture Transactions [Member] | Clark Dietrich [Member]
Percent of interest by unconsolidated affiliates	25.00%
Joint Venture Transactions [Member] | Gestamp Worthington Wind Steel, LLC [Member]
Percent of interest by unconsolidated affiliates	50.00%
Joint Venture Transactions [Member] | LEFCO Worthington, LLC [Member]
Percent of interest by unconsolidated affiliates	49.00%
Joint Venture Transactions [Member] | Samuel Steel Pickling Company [Member]
Percent of interest by unconsolidated affiliates	31.00%
Joint Venture Transactions [Member] | Serviacero Planos, S. de R.L. de C.V. [Member]
Percent of interest by unconsolidated affiliates	50.00%
Joint Venture Transactions [Member] | TWB Company, L.L.C. [Member]
Percent of interest by unconsolidated affiliates	45.00%
Joint Venture Transactions [Member] | Worthington Armstrong Venture [Member]
Percent of interest by unconsolidated affiliates	50.00%
Joint Venture Transactions [Member] | Worthington Modern Steel Framing Manufacturing Co., Ltd [Member]
Percent of interest by unconsolidated affiliates	40.00%
Joint Venture Transactions [Member] | Worthington Specialty Processing [Member]
Percent of interest by unconsolidated affiliates	51.00%
Worthington Armstrong Venture [Member]
Cumulative distributions in excess of investment	$ 7,844,000	$ 10,715,000