Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Feb. 28, 2015	May 31, 2014
Condensed Consolidated Balance Sheets
Accounts receivable, allowances (in dollars)	$ 5.8	$ 6.2
Property, plant and equipment, accumulated depreciation (in dollars)	371.4	424.3
Intangible assets, accumulated amortization (in dollars)	$ 21.6	$ 36.2
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized shares	250,000us-gaap_PreferredStockSharesAuthorized	250,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, issued shares	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized shares	100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized
Common stock, issued shares	44,953,514us-gaap_CommonStockSharesIssued	44,674,186us-gaap_CommonStockSharesIssued
Treasury stock, shares	5,137,409us-gaap_TreasuryStockShares	5,113,939us-gaap_TreasuryStockShares

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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