Annual report pursuant to Section 13 and 15(d)

Short-Term And Long-Term Investments And Restricted Deposits (Schedule Of Available-For-Sale Investments In A Continuous Unrealized Loss Position) (Details)

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Short-Term And Long-Term Investments And Restricted Deposits (Schedule Of Available-For-Sale Investments In A Continuous Unrealized Loss Position) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses $ (841) $ (790)
Less Than 12 Months, Fair Value 61,948 58,413
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value      
U.S. Treasury Securities And Obligations Of U.S. Government Corporations And Agencies [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (13) (140)
Less Than 12 Months, Fair Value 2,184 9,246
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value      
Corporate Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (751) (586)
Less Than 12 Months, Fair Value 23,040 40,341
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value      
Municipal Securities, General Obligation [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (26) (6)
Less Than 12 Months, Fair Value 3,710 1,131
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value      
Municipal Securities, Revenue [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (34) (15)
Less Than 12 Months, Fair Value 12,597 2,419
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value      
Asset Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (17) (43)
Less Than 12 Months, Fair Value 20,417 5,276
12 Months or More, Unrealized Losses      
12 Months or More, Fair Value