Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jan. 31, 2015	Apr. 30, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, no par value
Common stock, shares authorized	40,000,000us-gaap_CommonStockSharesAuthorized	40,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	15,894,599us-gaap_CommonStockSharesIssued	15,476,298us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	15,894,599us-gaap_CommonStockSharesOutstanding	15,476,298us-gaap_CommonStockSharesOutstanding

Face amount per share of no-par value 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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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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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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