Condensed Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 160	$ 160
Percentage of noncumulative preferred stock	10.00%	10.00%
Preferred stock, par value	$ 50	$ 50
Preferred stock, shares authorized	640us-gaap_PreferredStockSharesAuthorized	640us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	640us-gaap_PreferredStockSharesIssued	640us-gaap_PreferredStockSharesIssued
Preferred stock, shares outstanding	640us-gaap_PreferredStockSharesOutstanding	640us-gaap_PreferredStockSharesOutstanding
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	15,000,000us-gaap_CommonStockSharesAuthorized	15,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	4,860,635us-gaap_CommonStockSharesIssued	4,859,871us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	4,860,635us-gaap_CommonStockSharesOutstanding	4,859,871us-gaap_CommonStockSharesOutstanding

Percentage of noncumulative preferred stock.

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- Definition

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 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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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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