FAIR VALUE OF ASSETS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2010	Sep. 30, 2011
Reconciliation of changes in Level 3 assets measured at fair value
Balance at the beginning of the period	$ 5,392	$ 2,251
Total Unrealized Gains	9
Sales and Other Settlements	(3,150)
Balance at the end of the period	2,251	2,251
Maximum percentage of assets measured using Level 3 valuation methodologies to total assets (as a percent)	1.00%	1.00%
Corporate equity securities \| Recurring basis
Investments measured at fair value on a recurring basis
Short-term investments	158
Corporate equity securities \| Recurring basis \| Level 1
Investments measured at fair value on a recurring basis
Short-term investments	158
Auction-rate securities \| Recurring basis
Investments measured at fair value on a recurring basis
Other assets	2,251	2,251
Auction-rate securities \| Recurring basis \| Level 3
Investments measured at fair value on a recurring basis
Other assets	2,251	2,251
Corporate Debt Securities and Other Obligations \| Recurring basis
Investments measured at fair value on a recurring basis
Short-term investments	19,416	4,579
Corporate Debt Securities and Other Obligations \| Recurring basis \| Level 2
Investments measured at fair value on a recurring basis
Short-term investments	19,416	4,579
Recurring basis
Investments measured at fair value on a recurring basis
Money market funds		16,640
Total	25,608	27,942
Recurring basis \| Deferred Compensation Plan Assets
Investments measured at fair value on a recurring basis
Other assets	3,783	4,472
Recurring basis \| Deferred Compensation Plan Assets \| Level 1
Investments measured at fair value on a recurring basis
Other assets	3,783	4,472
Recurring basis \| Level 1
Investments measured at fair value on a recurring basis
Money market funds		16,640
Total	3,941	21,112
Recurring basis \| Level 2
Investments measured at fair value on a recurring basis
Total	19,416	4,579
Recurring basis \| Level 3
Investments measured at fair value on a recurring basis
Total	2,251	2,251
Auction-rate securities
Reconciliation of changes in Level 3 assets measured at fair value
Balance at the beginning of the period	5,392	2,251
Total Unrealized Gains	9
Sales and Other Settlements	(3,150)
Balance at the end of the period	$ 2,251	$ 2,251

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

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- Definition

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.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

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-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

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- Definition

This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ References

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- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification

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- Definition

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 8, 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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