v2.4.0.6
Investments (Schedule Of Contractual Maturities Of Fixed Maturity Investments) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Investment Holdings [Line Items]    
Trading, Amortized Cost, Due in less than one year $ 385,039  
Trading, Amortized Cost, Due after one through five years 2,348,627  
Trading, Amortized Cost, Due after five through ten years 619,557  
Trading, Amortized Cost, Due after ten years 120,767  
Trading, Amortized Cost 4,129,942  
Trading, Fair Value, Due in less than one year 385,831  
Trading, Fair Value, Due after one through five years 2,357,996  
Trading, Fair Value, Due after five through ten years 636,756  
Trading, Fair Value, Due after ten years 130,754  
Trading, Fair Value 4,176,827 4,291,465
Available for Sale, Amortized Cost, Due in less than one year 437  
Available for Sale, Amortized Cost, Due after one through five years 8,861  
Available for Sale, Amortized Cost, Due after five through ten years 8,658  
Available for Sale, Amortized Cost, Due after ten years 3,725  
Available for Sale, Amortized Cost 113,131 130,699
Available for Sale, Fair Value, Due in less than one year 428  
Available for Sale, Fair Value, Due after one through five years 9,348  
Available for Sale, Fair Value, Due after five through ten years 9,335  
Available for Sale, Fair Value, Due after ten years 4,194  
Available for Sale, Fair Value 125,292 142,052
Debt Securities, Amortized Cost, Due in less than one year 385,476  
Debt Securities, Amortized Cost, Due after one through five years 2,357,488  
Debt Securities, Amortized Cost, Due after five through ten years 628,215  
Debt Securities, Amortized Cost, Due after ten years 124,492  
Debt Securities, Amortized Cost 4,243,073  
Debt Securities, Fair Value, Due in less than one year 386,259  
Debt Securities, Fair Value, Due after one through give years 2,367,344  
Debt Securities, Fair Value, Due after five through ten years 646,091  
Debt Securities, Fair Value, Due after ten years 134,948  
Debt Securities, Fair Value 4,302,119  
Mortgage-backed [Member]
   
Investment Holdings [Line Items]    
Trading, Amortized Cost 649,942  
Trading, Fair Value 659,479  
Available for Sale, Amortized Cost 86,800  
Available for Sale, Fair Value 97,126  
Debt Securities, Amortized Cost 736,742  
Debt Securities, Fair Value 756,605  
Asset-backed [Member]
   
Investment Holdings [Line Items]    
Trading, Amortized Cost 6,010  
Trading, Fair Value 6,011  
Available for Sale, Amortized Cost 4,650  
Available for Sale, Fair Value 4,861  
Debt Securities, Amortized Cost 10,660  
Debt Securities, Fair Value $ 10,872