Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Feb. 28, 2015	Aug. 31, 2014	Feb. 28, 2014
Condensed Consolidated Balance Sheets [Abstract]
Receivables, allowance, current	$ 2,517	$ 2,857	$ 3,520
Receivables, allowance, noncurrent	$ 2,007	$ 2,000	$ 0
Preferred stock, par value	$ 1	$ 1	$ 1
Preferred stock, authorized	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Preferred stock, issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par value	$ 1	$ 1	$ 1
Common stock, authorized	25,000,000us-gaap_CommonStockSharesAuthorized	25,000,000us-gaap_CommonStockSharesAuthorized	25,000,000us-gaap_CommonStockSharesAuthorized
Common stock, issued	18,675,000us-gaap_CommonStockSharesIssued	18,636,000us-gaap_CommonStockSharesIssued	18,633,000us-gaap_CommonStockSharesIssued
Treasury stock, shares	6,802,000us-gaap_TreasuryStockShares	6,196,000us-gaap_TreasuryStockShares	5,777,000us-gaap_TreasuryStockShares

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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A valuation allowance for receivables due to an Entity for more than one year from the balance sheet date that are expected to be uncollectible.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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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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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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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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