Investments in Marketable Securities (Held to Maturity Securities, by Maturity) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities	$ 108,000us-gaap_AvailableForSaleSecurities	$ 107,000us-gaap_AvailableForSaleSecurities
Letters of Credit Outstanding, Amount	1,400,000
Held-to-maturity Securities, Current	316,000us-gaap_HeldToMaturitySecuritiesCurrent	534,000us-gaap_HeldToMaturitySecuritiesCurrent
Held-to-maturity Securities, Noncurrent	1,270,000	1,057,000
Held-to-maturity Securities, Total	1,586,000us-gaap_HeldToMaturitySecurities	1,591,000us-gaap_HeldToMaturitySecurities
Mutual Funds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities	60,000	59,000
Cash/Money Market Accounts [Member]
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities	48,000	48,000
Held-to-maturity Securities, Current	82,000	204,000
Held-to-maturity Securities, Noncurrent	0	0
Held-to-maturity Securities, Total	82,000	204,000
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Current	105,000	105,000
Held-to-maturity Securities, Noncurrent	1,178,000	965,000
Held-to-maturity Securities, Total	1,283,000	1,070,000
US Government Agencies Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Current	129,000	225,000
Held-to-maturity Securities, Noncurrent	92,000	92,000
Held-to-maturity Securities, Total	$ 221,000	$ 317,000

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

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-Name Accounting Standards Codification

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity, not expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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