Marketable Securities (Details Textual) (USD $)	6 Months Ended	12 Months Ended
Jun. 30, 2012	Dec. 31, 2011
Marketable Securities (Textual) [Abstract]
Fair market value of investment securities exceeds cost basis	$ 552,000
Other-than-temporary impairments recorded for securities	0
Change in value of available-for-sale securities	91,000	(49,000)
Estimated taxes of change in value of available-for-sale securities	60,000	33,000
Gross unrealized holding gains	672,000
Gross unrealized holding losses	120,000
Available-for-sale securities with remaining maturity term of greater than five years	$ 0
Certificates of deposit [Member]
Marketable Securities (Additional Textual) [Abstract]
Average maturity period	2 years 9 months 7 days
U.S. Treasury and agency notes [Member]
Marketable Securities (Additional Textual) [Abstract]
Average maturity period	2 years 3 months 22 days
Corporate notes [Member]
Marketable Securities (Additional Textual) [Abstract]
Average maturity period	2 years 1 month 28 days
Municipal notes [Member]
Marketable Securities (Additional Textual) [Abstract]
Average maturity period	2 years 4 months 24 days

Available for sale securities, average maturity period.

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Available for sale securities, fair market value exceeds cost basis, by amount.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

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-Name Accounting Standards Codification

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Investments in debt and equity securities which are categorized neither as held-to-maturity nor trading and which are intended to be sold or mature more than one year from the balance sheet date or operating cycle, if longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

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Net of tax amount of the appreciation (loss) in the value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) losses.

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Tax effect, net of reclassification adjustments, of the change in the balance sheet adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency of the reporting entity. Also includes the following: gain (loss) on foreign currency forward exchange contracts; foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; and gain (loss) on a derivative instrument or nonderivative financial instrument that may give rise to a foreign currency transaction gain (loss) that has been designated and qualified as a hedging instrument for hedging of the foreign currency exposure of a net investment in a foreign operation.

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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