Investments (Tables)

9 Months Ended

Sep. 30, 2012

Investments

Summary of contract maturity of available-for-sale securities

One year or less	63	%
After one year but within two years	24	%
After two years but within three years	13	%
Total	100	%

Summary of investments

The following is a summary of our investments (in thousands):

								Other-Than-
								Temporary
	Amortized		Unrealized					Impairment			Estimated
September 30, 2012	Cost		Gains		Losses			Loss			Fair Value
Short-term investments:
Corporate debt securities	$	135,045	$	146	$	(7	)	$	—		$	135,184
Debt securities issued by U.S. government agencies	18,015		6		—			—			18,021
Debt securities issued by states of the United States and political subdivisions of the states	11,100		7		—			—			11,107
Total securities with a maturity of one year or less	164,160		159		(7		)	—			164,312
Corporate debt securities	55,374		127		(37		)	—			55,464
Debt securities issued by U.S. government agencies	13,177		36		(83		)	—			13,130
Debt securities issued by the U.S. Treasury	13,455		31		—			—			13,486
Debt securities issued by states of the United States and political subdivisions of the states	12,572		49		(3		)	—			12,618
Total securities with a maturity of more than one year	94,578		243		(123		)	—			94,698
Subtotal	$	258,738	$	402	$	(130	)	$	—		$	259,010
Equity securities:
Current portion (included in Other current assets)	$	1,579	$	2,491	$	—		$	(880	)	$	3,190
Long-term portion (included in Deposits and other assets)	625		—		—			—			625
Subtotal	$	2,204	$	2,491	$	—		$	(880	)	$	3,815
	$	260,942	$	2,893	$	(130	)	$	(880	)	$	262,825

								Other-Than-
								Temporary
	Amortized		Unrealized					Impairment			Estimated
December 31, 2011	Cost		Gains		Losses			Loss			Fair Value
Short-term investments:
Corporate debt securities	$	109,842	$	13	$	(255	)	$	—		$	109,600
Debt securities issued by U.S. government agencies	53,723		35		(5		)	—			53,753
Debt securities issued by the U.S. Treasury	2,353		3		—			—			2,356
Debt securities issued by states of the United States and political subdivisions of the states	16,141		4		(3		)	—			16,142
Total securities with a maturity of one year or less	182,059		55		(263		)	—			181,851
Corporate debt securities	57,632		21		(331		)	—			57,322
Debt securities issued by U.S. government agencies	26,754		—		(67		)	—			26,687
Debt securities issued by states of the United States and political subdivisions of the states	12,331		19		(23		)	—			12,327
Total securities with a maturity of more than one year	96,717		40		(421		)	—			96,336
Subtotal	$	278,776	$	95	$	(684	)	$	—		$	278,187
Equity securities:
Current portion (included in Other current assets)	$	1,538	$	624	$	—		$	(880	)	$	1,282
Long-term portion (included in Deposits and other assets)	625		—		—			—			625
Subtotal	$	2,163	$	624	$	—		$	(880	)	$	1,907
	$	280,939	$	719	$	(684	)	$	(880	)	$	280,094

Schedule of investments temporarily impaired

Investments we considered to be temporarily impaired at September 30, 2012 were as follows (in thousands):

		Less than 12 months of temporary impairment
	Number of Investments	Estimated Fair Value		Unrealized Losses
Corporate debt securities	24	$	37,348	$	(44	)
Debt securities issued by U.S. government agencies	2	7,056		(83		)
Debt securities issued by the U.S. Treasury
Debt securities issued by states of the United States and political subdivisions of the states	1	5,200		(3		)
Total temporarily impaired securities	27	$	49,604	$	(130	)