MARKETABLE SECURITIES (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
Available-for-sale marketable securities
Amortized Cost	$ 185,172	$ 560,661
Gross Unrealized Gains	719	3,582
Gross Unrealized Losses	(210)	(246)
Estimated Fair Value	185,681	563,997
Contractual maturities of debt securities classified as available-for-sale
Due in one year or less, Amortized Cost	98,145
Due after one year through five years, Amortized Cost	81,292
Total, Amortized Cost	179,437
Due in one year or less, Estimated Fair Value	98,410
Due after one year through five years, Estimated Fair Value	81,639
Total, Estimated Fair Value	180,049
Total debt securities
Available-for-sale marketable securities
Amortized Cost	179,437	547,765
Gross Unrealized Gains	719	1,164
Gross Unrealized Losses	(107)	(246)
Estimated Fair Value	180,049	548,683
Corporate debt securities
Available-for-sale marketable securities
Amortized Cost	67,833	237,406
Gross Unrealized Gains	116	773
Gross Unrealized Losses	(41)	(16)
Estimated Fair Value	67,908	238,163
States of the U.S. and state political subdivisions
Available-for-sale marketable securities
Amortized Cost	111,604	110,478
Gross Unrealized Gains	603	373
Gross Unrealized Losses	(66)	(230)
Estimated Fair Value	112,141	110,621
U.S. Treasury securities
Available-for-sale marketable securities
Amortized Cost		199,881
Gross Unrealized Gains		18
Estimated Fair Value		199,899
Marketable equity security
Available-for-sale marketable securities
Amortized Cost	5,735	12,896
Gross Unrealized Gains		2,418
Gross Unrealized Losses	(103)
Estimated Fair Value	$ 5,632	$ 15,314

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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Total of debt securities categorized neither as held-to-maturity nor trading which are intended be sold or mature within one year from the balance sheet date or the normal operating cycle, whichever is longer.

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