Cash And Cash Equivalents And Investments (Summary Of Cash And Cash Equivalents And Investments By Balance Sheet Classification) (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010
Cash And Cash Equivalents And Investments
Cash and cash equivalents, cost	$ 193,798		$ 356,533
Cash and cash equivalents, fair value	193,798	[1]	356,533	[1]
Short term investments, cost	38,073		90,466
Short-term investments, fair value	37,132	[1]	90,284	[1]
Long term investments, cost	26,086		45,647
Long-term investments, fair value	25,799	[1]	45,466	[1]
Total cash and cash equivalents and investments, cost	257,957		492,646
Total cash and cash equivalents and investments, fair value	$ 256,729	[1]	$ 492,283	[1]

[1] See Note 16 - Fair Value Measurements for details regarding fair value measurements.