Investments (Maturities Of Investments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Investments [Abstract]
Due in less than one year, Amortized Cost	$ 121,560
Due after 1 through 5 years, Amortized Cost	200,515
Due after 5 through 10 years, Amortized Cost	2,800
Due after 10 years, Amortized Cost	101,320
Total, Amortized Cost	426,195
Due in less than one year, Fair Value	121,889
Due after 1 through 5 years, Fair Value	200,907
Due after 5 through 10 years, Fair Value	2,800
Due after 10 years, Fair Value	95,336
Total, Fair Value	$ 420,932	$ 473,756

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

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