Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Apr. 30, 2015	Jul. 31, 2014
Stockholders’ equity:
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued (in shares)	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares)	31,151,557us-gaap_CommonStockSharesIssued	31,016,469us-gaap_CommonStockSharesIssued
Treasury stock, shares (in shares)	15,033,317us-gaap_TreasuryStockShares	14,857,582us-gaap_TreasuryStockShares

Face amount or stated value per share of common stock.

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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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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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