MARKETABLE SECURITIES (Tables)

6 Months Ended

Jun. 30, 2011

MARKETABLE SECURITIES

Schedule of available-for-sale marketable securities

        At June 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			$	116,492	$	249	$	(9	)	$	116,732
States of the U.S. and state political subdivisions				112,593		589		(42	)		113,140
U.S. Treasury securities				49,987		12		—			49,999
	Total debt securities			279,072		850		(51	)		279,871
	Equity security			7,631		1,495		—			9,126
		Total marketable securities	$	286,703	$	2,345	$	(51	)	$	288,997

        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 June 30, 2011 are as follows (in thousands):

		Amortized Cost		Estimated Fair Value
Due in one year or less		$	195,082	$	195,443
Due after one year through five years			83,990		84,428
	Total	$	279,072	$	279,871

Summary of investments with continuous unrealized loss position

		June 30, 2011					December 31, 2010
		Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate debt securities		$	12,271	$	(9	)	$	34,552	$	(16	)
States of the U.S. and state political subdivisions			6,764		(42	)		39,171		(230	)
	Total	$	19,035	$	(51	)	$	73,723	$	(246	)

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

	Three Months Ended June 30,					Six Months Ended June 30,
	2011		2010			2011			2010
	(In thousands)
Proceeds from sales and maturities of available-for-sale marketable securities	$	215,139	$	170,878		$	413,904		$	371,868
Gross realized gains		1,022		83			1,916			4,332
Gross realized losses		—		(7	)		(18	)		(7	)