Summary Of Significant Accounting Policies (Marketable Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale	$ 135,634	$ 153,380
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale	$ 135,634	$ 153,380

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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