Investment Portfolio (Tables)

6 Months Ended

Jun. 30, 2012

Investment Portfolio [Abstract]

Components of investment portfolio

(Amounts in thousands)	June 30, 2012		December 31, 2011
Cash	$	2,126,441	$	2,016,451
Money markets		421,794		555,659
Deposits		22		64
Cash and cash equivalents (substantially restricted)		2,548,257		2,572,174
Short-term investments (substantially restricted)		524,055		522,024
Available-for-sale investments (substantially restricted)		85,281		102,771
Total investment portfolio	$	3,157,593	$	3,196,969

Available for sale Investments (substantially restricted)

	June 30, 2012
(Amounts in thousands, except net average price)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Net Average Price
Residential mortgage-backed securities-agencies	$	45,828	$	3,786	$	—	$	49,614	$	109.04
Other asset-backed securities		8,615		18,082		—		26,697		6.16
United States government agencies		7,959		1,011		—		8,970		99.67
Total	$	62,402	$	22,879	$	—	$	85,281	$	17.48

	December 31, 2011
(Amounts in thousands, except net average price)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Net Average Price
Residential mortgage-backed securities - agencies	$	65,211	$	4,501	$	—	$	69,712	$	107.63
Other asset-backed securities		8,951		15,281		—		24,232		5.49
United States government agencies		7,723		1,104		—		8,827		98.08
Total	$	81,885	$	20,886	$	—	$	102,771	$	21.83

Net securities gain

	Three Months Ended June 30,					Six Months Ended June 30,
(Amounts in thousands)	2012		2011			2012		2011
Realized gains from available-for-sale investments	$	—	$	(32,820	)	$	—	$	(32,820	)
Other-than-temporary impairments from available-for-sale investments		—		4			—		4
Net securities gains	$	—	$	(32,816	)	$	—	$	(32,816	)

Investment ratings

	June 30, 2012							December 31, 2011
(Dollars in thousands)	Number of Securities		Fair Value		Percent of Investments			Number of Securities		Fair Value		Percent of Investments
AAA, including United States agencies		20	$	58,275		68	%		24	$	78,267		76	%
Below investment grade		58		27,006		32	%		60		24,504		24	%
Total		78	$	85,281		100	%		84	$	102,771		100	%

Contractual maturities

	June 30, 2012				December 31, 2011
(Amounts in thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	1,000	$	1,023	$	—	$	—
After one year through five years		6,959		7,948		7,723		8,827
Mortgage-backed and other asset-backed securities		54,443		76,310		74,162		93,944
Total	$	62,402	$	85,281	$	81,885	$	102,771