Short-term Investments Short-term Investments (Tables)

3 Months Ended

Mar. 31, 2014

Short-Term Investments And Fair Value Measurement [Abstract]

Available-For-Sale Securities Reported At Fair Value

The following tables summarize, by major security type, the Company’s assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy:

	As of March 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	1,069,050	$	—	$	—		$	1,069,050
Level 1 securities:
Money market funds	94,103		—		—			94,103
Level 2 securities:
Corporate debt securities	328,233		1,333		(218		)	329,348
Government securities	136,374		319		(9		)	136,684
Asset backed securities	3,382		4		—			3,386
Certificate of deposits	23,425		—		—			23,425
Agency securities	17,950		—		—			17,950
Total (1)	$	1,672,517	$	1,656	$	(227	)	$	1,673,946

	As of December 31, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	483,959	$	—	$	—		$	483,959
Level 1 securities:
Money market funds	126,208		—		—			126,208
Level 2 securities:
Corporate debt securities	316,465		1,245		(654		)	317,056
Government securities	143,812		287		(18		)	144,081
Asset and mortgage-backed securities	93,118		229		(418		)	92,929
Certificate of deposits	23,425		—		—			23,425
Agency securities	17,951		—		(2		)	17,949
Total (2)	$	1,204,938	$	1,761	$	(1,092	)	$	1,205,607

(1) Includes $1,157.5 million that is included in cash and cash equivalents, $510.8 million included in short-term investments and $5.7 million of restricted cash that is included in other non-current assets related to workers compensation deposits.

(2) Includes $605.0 million that is included in cash and cash equivalents, $595.4 million included in short-term investments and $5.2 million of restricted cash that is included in other non-current assets related to workers compensation deposits.

Estimated Fair Value Of Short-Term Investments By Contractual Maturity

The estimated fair value of short-term investments by contractual maturity as of March 31, 2014 is as follows:

	(in thousands)
Due within one year	$	204,050
Due after one year and through 5 years	306,743
Due after 5 years and through 10 years	—
Due after 10 years	—
Total short-term investments	$	510,793