MARKETABLE SECURITIES

3 Months Ended

Mar. 31, 2011

MARKETABLE SECURITIES

MARKETABLE SECURITIES

NOTE 5—MARKETABLE SECURITIES

        At March 31, 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		$	217,940	$	701	$	(19	)	$	218,622
States of the U.S. and state political subdivisions			110,192		407		(100	)		110,499
U.S. Treasury securities			124,937		25		—			124,962
	Total debt securities		453,069		1,133		(119	)		454,083
	Equity security		10,224		4,583		—			14,807
	Total marketable securities	$	463,293	$	5,716	$	(119	)	$	468,890

        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 securities		12,896		2,418		—			15,314
	Total marketable securities	$	560,661	$	3,582	$	(246	)	$	563,997

        The net unrealized gains in the tables above are included in accumulated other comprehensive income for their respective periods.

        The contractual maturities of debt securities classified as available-for-sale at March 31, 2011 are as follows (in thousands):

		Amortized Cost		Estimated Fair Value
Due in one year or less		$	359,970	$	360,676
Due after one year through five years			93,099		93,407
	Total	$	453,069	$	454,083

        The following table summarizes investments in marketable securities that have been in a continuous unrealized loss position for less than twelve months (in thousands):

		March 31, 2011					December 31, 2010
		Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate debt securities		$	14,848	$	(19	)	$	34,552	$	(16	)
States of the U.S. and state political subdivisions			15,665		(100	)		39,171		(230	)
	Total	$	30,513	$	(119	)	$	73,723	$	(246	)

        At March 31, 2011 and December 31, 2010, there are no investments in marketable securities that have been in a continuous unrealized loss position for twelve months or longer.

        Substantially all of the Company's debt securities are rated investment grade. Because the Company does not intend to sell any marketable securities and it is not more likely than not that the Company will be required to sell any marketable securities before recovery of their amortized cost bases, which may be maturity, the Company does not consider any of its marketable securities to be other-than-temporarily impaired at March 31, 2011.

        The following table presents the proceeds from sales and maturities of available-for-sale marketable securities and the related gross realized gains and losses (in thousands):

	Three Months Ended March 31,
	2011			2010
Proceeds from sales and maturities of available-for-sale marketable securities	$	198,765		$	200,990
Gross realized gains		894			4,249
Gross realized losses		(18	)		—

        Gross realized gains and losses from the sale of marketable securities and from the sale of investments are included in "Other income, net" in the accompanying consolidated statement of operations.