MARKETABLE SECURITIES (Tables)

9 Months Ended

Sep. 30, 2011

MARKETABLE SECURITIES

Schedule of available-for-sale marketable securities

        At September 30, 2011, available-for-sale marketable securities are as follows (in thousands):

			Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Corporate debt securities			$	67,833	$	116	$	(41	)	$	67,908
States of the U.S. and state political subdivisions				111,604		603		(66	)		112,141
	Total debt securities			179,437		719		(107	)		180,049
	Equity security			5,735		—		(103	)		5,632
		Total marketable securities	$	185,172	$	719	$	(210	)	$	185,681

        At December 31, 2010, available-for-sale marketable securities are as follows (in thousands):

			Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Corporate debt securities			$	237,406	$	773	$	(16	)	$	238,163
States of the U.S. and state political subdivisions				110,478		373		(230	)		110,621
U.S. Treasury securities				199,881		18		—			199,899
	Total debt securities			547,765		1,164		(246	)		548,683
	Equity security			12,896		2,418		—			15,314
		Total marketable securities	$	560,661	$	3,582	$	(246	)	$	563,997

Schedule of contractual maturities of debt securities classified as available-for-sale

        The contractual maturities of debt securities classified as available-for-sale at September 30, 2011 are as follows (in thousands):

		Amortized Cost		Estimated Fair Value
Due in one year or less		$	98,145	$	98,410
Due after one year through five years			81,292		81,639
	Total	$	179,437	$	180,049

Summary of investments with continuous unrealized loss position for less than twelve months

		September 30, 2011					December 31, 2010
		Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate debt securities		$	16,995	$	(41	)	$	34,552	$	(16	)
States of the U.S. and state political subdivisions			26,224		(66	)		39,171		(230	)
	Total	$	43,219	$	(107	)	$	73,723	$	(246	)

Schedule of proceeds from maturities and sales of available-for-sale marketable securities and the related gross realized gains and losses

	Three Months Ended September 30,				Nine Months Ended September 30,
	2011		2010		2011			2010
	(In thousands)
Proceeds from maturities and sales of available-for-sale marketable securities	$	128,287	$	240,584	$	542,191		$	612,452
Gross realized gains		387		328		2,303			4,660
Gross realized losses		—		—		(18	)		(7	)