Fair Value Of Financial Instruments (Reconciliation Of Balances For Assets And Liabilities Measured At Fair Value) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended			3 Months Ended		3 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Short-Term Investments [Member]	Sep. 30, 2011 Short-Term Investments [Member]	Dec. 31, 2010 Long-Term Investments [Member]	Sep. 30, 2011 Long-Term Investments [Member]	Jun. 30, 2011 Long-Term Investments [Member]		Mar. 31, 2011 Long-Term Investments [Member]	Sep. 30, 2011 Equity Method Investment [Member]	Jun. 30, 2011 Equity Method Investment [Member]	Mar. 31, 2011 Equity Method Investment [Member]
Beginning balance								$ 55,858	$ 77,553		$ 78,747	$ 52,124	$ 41,285	$ 30,724
Adjustment to previously recognized unrealized loss on investments included in other comprehensive income								12,192	3,129		(1,119)
Realized loss on investments									(842)
Income from equity method investment	1,915	(4,562)	15,103	(8,351)								1,915	10,639	2,549
Additional investment in equity method investments												4,508	200	8,012
Other-than-temporary impairment on auction rate securities								(17,551)
Liquidation of investments								(125)	(10,625)		(75)
Transfers between long term and short term					63,580		78,747
Transfers out of Level 3								(50,374)	(13,357)	[1]
Transfers into Level 3						50,374
Ending balance						$ 50,374			$ 55,858		$ 77,553	$ 58,547	$ 52,124	$ 41,285

[1] Transferred from Level 3 to Level 2 which has more observable market data due to increased market activity for asset-backed securities.