INVESTMENTS (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Held to Maturity and Available-for-sale
Held to maturity and available-for-sale securities, Amortized Cost	$ 308,574	$ 98,589
Held to maturity and available-for-sale securities, Gross Unrealized Holding Gains	56	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	308,630	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	325,353	118,424
Short-term \| U.S. Treasuries
Held-to-Maturity
Amortized Cost		16,040
Fair Value		16,040
Short-term \| Certificates of deposit
Held-to-Maturity
Amortized Cost	6,515	2,201
Fair Value	6,515	2,201
Short-term \| Municipal securities
Held-to-Maturity
Amortized Cost	302,059	77,038
Gross Unrealized Holding Gains	56
Gross Unrealized Holding Losses		11
Fair Value	302,115	77,027
Continuous Unrealized Loss Position less than 12 Months		11
Short-term \| Auction rate securities
Trading
Fair Value	6,998	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	$ 9,725	$ 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.

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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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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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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 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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