v2.4.0.6
Investments (Schedule Of Contractual Maturities Of Fixed Maturity Investments) (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Investment Holdings [Line Items]    
Trading, Amortized Cost, Due in less than one year $ 405,210  
Trading, Amortized Cost, Due after one through five years 2,606,528  
Trading, Amortized Cost, Due after five through ten years 625,279  
Trading, Amortized Cost, Due after ten years 130,574  
Trading, Amortized Cost 4,890,251  
Trading, Fair Value, Due in less than one year 405,547  
Trading, Fair Value, Due after one through five years 2,615,915  
Trading, Fair Value, Due after five through ten years 646,130  
Trading, Fair Value, Due after ten years 143,134  
Trading, Fair Value 4,948,955 4,291,465
Available for Sale, Amortized Cost, Due in less than one year 112  
Available for Sale, Amortized Cost, Due after one through five years 8,358  
Available for Sale, Amortized Cost, Due after five through ten years 6,200  
Available for Sale, Amortized Cost, Due after ten years 2,145  
Available for Sale, Amortized Cost 96,647 130,699
Available for Sale, Fair Value, Due in less than one year 89  
Available for Sale, Fair Value, Due after one through five years 8,761  
Available for Sale, Fair Value, Due after five through ten years 6,779  
Available for Sale, Fair Value, Due after ten years 2,309  
Available for Sale, Fair Value 108,102 142,052
Debt Securities, Amortized Cost, Due in less than one year 405,322  
Debt Securities, Amortized Cost, Due after one through five years 2,614,886  
Debt Securities, Amortized Cost, Due after five through ten years 631,479  
Debt Securities, Amortized Cost, Due after ten years 132,719  
Debt Securities, Amortized Cost 4,986,898  
Debt Securities, Fair Value, Due in less than one year 405,636  
Debt Securities, Fair Value, Due after one through give years 2,624,676  
Debt Securities, Fair Value, Due after five through ten years 652,909  
Debt Securities, Fair Value, Due after ten years 145,443  
Debt Securities, Fair Value 5,057,057  
Asset-backed [Member]
   
Investment Holdings [Line Items]    
Trading, Amortized Cost 7,356  
Trading, Fair Value 7,466  
Available for Sale, Amortized Cost 4,499  
Available for Sale, Fair Value 4,731  
Debt Securities, Amortized Cost 11,855  
Debt Securities, Fair Value 12,197  
Mortgage-backed [Member]
   
Investment Holdings [Line Items]    
Trading, Amortized Cost 1,115,304  
Trading, Fair Value 1,130,763  
Available for Sale, Amortized Cost 75,333  
Available for Sale, Fair Value 85,433  
Debt Securities, Amortized Cost 1,190,637  
Debt Securities, Fair Value $ 1,216,196