Quarterly report pursuant to Section 13 or 15(d)

Short-Term And Long-Term Investments And Restricted Deposits (Fair Value Of Available-For-Sale Investments With Gross Unrealized Losses By Investment Type And Length Of Time) (Details)

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Short-Term And Long-Term Investments And Restricted Deposits (Fair Value Of Available-For-Sale Investments With Gross Unrealized Losses By Investment Type And Length Of Time) (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses $ (35) $ (841)
Less Than 12 Months, Fair Value 8,316 61,948
12 Months or More, Unrealized Losses (2) 0
12 Months or More, Fair Value 202 0
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 (4) (13)
Less Than 12 Months, Fair Value 1,196 2,184
12 Months or More, Unrealized Losses (2) 0
12 Months or More, Fair Value 202 0
Corporate Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (6) (751)
Less Than 12 Months, Fair Value 5,295 23,040
12 Months or More, Unrealized Losses 0 0
12 Months or More, Fair Value 0 0
Municipal Securities, General Obligation [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses 0 (26)
Less Than 12 Months, Fair Value 0 3,710
12 Months or More, Unrealized Losses 0 0
12 Months or More, Fair Value 0 0
Municipal Securities, Revenue [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses (25) (34)
Less Than 12 Months, Fair Value 1,825 12,597
12 Months or More, Unrealized Losses 0 0
12 Months or More, Fair Value 0 0
Asset Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Less Than 12 Months, Unrealized Losses 0 (17)
Less Than 12 Months, Fair Value 0 20,417
12 Months or More, Unrealized Losses 0 0
12 Months or More, Fair Value $ 0 $ 0