INVESTMENTS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Held to Maturity and Available-for-sale
Held to maturity and available-for-sale securities, Amortized Cost	$ 142,388	$ 98,589
Held to maturity and available-for-sale securities, Gross Unrealized Holding Gains	45	2,483
Held to maturity and available-for-sale securities, Gross Unrealized Holding Losses		11
Held to maturity and available-for-sale securities, Fair Value	142,433	101,061
Held to maturity and available-for-sale securities, Continuous Unrealized Loss Position less than 12 Months		11
Held to Maturity, Available-for-sale, and Trading
Total Fair Value	160,195	118,424
Short-term \| U.S. Treasuries
Held-to-Maturity
Amortized Cost	11,019	16,040
Gross Unrealized Holding Gains	2
Fair Value	11,021	16,040
Short-term \| Certificates of deposit
Held-to-Maturity
Amortized Cost	11,515	2,201
Fair Value	11,515	2,201
Short-term \| Municipal securities
Held-to-Maturity
Amortized Cost	119,854	77,038
Gross Unrealized Holding Gains	43
Gross Unrealized Holding Losses		11
Fair Value	119,897	77,027
Continuous Unrealized Loss Position less than 12 Months		11
Short-term \| Auction rate securities
Trading
Fair Value	5,809	1,763
Long-term \| Auction rate securities
Available-for-sale
Amortized Cost		3,310
Gross Unrealized Holding Gains		2,483
Fair Value		5,793
Trading
Fair Value	$ 11,953	$ 15,600

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Represents the cost of debt and equity securities, which are categorized as held-to-maturity and available-for-sale, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Represents the excess of amortized cost basis over the fair value of securities that have been in a loss position for less than twelve months for those securities that are categorized as held-to-maturity and available-for-sale.

+ References

No definition available.

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Represents investments in debt securities which are categorized as held-to-maturity and available-for-sale; such investments are normally measured at amortized cost (carrying value) unless circumstances indicate that the value to be recovered from the investment is less than its carried amount. This element may be used in connection with the fair value disclosures required in footnote disclosures to the financial statements.

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Represents the gross unrealized gains for securities, at a point in time, which are categorized as held-to-maturity and available-for-sale securities.

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No definition available.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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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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Amount of investments in debt securities categorized as held-to-maturity valued at amortized cost, excludes other than temporary impairment (OTTI).

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This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for less than twelve months for those securities which are categorized as held-to-maturity.

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This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

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As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

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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 Trading Securities which consist of all investments in certain debt and equity securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for which an entity has elected the fair value option. Trading generally reflects active and frequent buying and selling, and trading securities are generally used with the objective of generating profits on short-term differences in price, but this category of investments may also include items which are not intended to be sold in the near term or for which the fair value option has been elected.

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