Marketable Securities and Fair Value Disclosures (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Summary of marketable securities
Available-for-Sale Securities, Amortized Cost	$ 9,802		$ 9,802		$ 10,282
Available-for-Sale Securities, Gross Unrealized Gains	0		0		0
Available-for-Sale Securities, Gross Unrealized Losses	(125)		(125)		(152)
Available-for-Sale Securities, Estimated fair value	9,677		9,677		10,130
The following table reconciles total other-than-temporary impairment losses to other-than-temporary losses recognized in earnings for the Company's available-for-sale securities
Total other-than-temporary losses	0	0	0	(4)
Less: portion of losses recorded in other comprehensive income	0	0	0	(4)
Net impairment losses recognized in earnings	0	0	0	0
Long-term: [Member] \| Auction rate securities [Member]
Summary of marketable securities
Available-for-Sale Securities, Amortized Cost	1,400		1,400		1,400
Available-for-Sale Securities, Gross Unrealized Gains	0		0		0
Available-for-Sale Securities, Gross Unrealized Losses	(110)		(110)		(131)
Available-for-Sale Securities, Estimated fair value	1,290		1,290		1,269
Short-term: [Member] \| Mutual fund deposits [Member]
Summary of marketable securities
Available-for-Sale Securities, Amortized Cost	8,402		8,402		8,882
Available-for-Sale Securities, Gross Unrealized Gains	0		0		0
Available-for-Sale Securities, Gross Unrealized Losses	(15)		(15)		(21)
Available-for-Sale Securities, Estimated fair value	$ 8,387		$ 8,387		$ 8,861

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

The amount of other than temporary impairment (OTTI) loss on a debt security, categorized as Available-for-sale, related to factors other than credit losses when the entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis. This amount, which includes the portion attributable to the noncontrolling interest, if any, is a portion of the deduction from the total impairment losses of investments (before taxes) presented on the income statement; this amount is also referred to as the amount incurred by the reporting entity or the consolidated entity.

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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