v2.4.0.8
Investments - Schedule of Investments Reconciliation (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost $ 2,665,870 $ 2,475,202
Other Investments, Original or amortized cost 4,087 2,599
Total investments, Original or amortized cost 2,669,957 2,477,801
Available-for-sale securities, Gross unrealized gains 94,070 151,460
Other investments, Gross unrealized gains 364 353
Investments, Gross unrealized gains 94,434 151,813
Available-for-sale securities, Gross unrealized losses (45,073) (7,965)
Other investments, Gross unrealized losses (13) (51)
Investments, Gross unrealized losses (45,086) (8,016)
Total Investments, Fair Value 2,714,867 2,618,697
Other investments 4,438 2,901
Total investments 2,719,305 2,621,598
U.S. treasury bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 16,635 42,671
Available-for-sale securities, Gross unrealized gains 811 1,260
Available-for-sale securities, Gross unrealized losses 0 0
Total Investments, Fair Value 17,446 43,931
U.S. agency bonds – mortgage-backed [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 1,221,606 962,649
Available-for-sale securities, Gross unrealized gains 16,336 30,998
Available-for-sale securities, Gross unrealized losses (19,456) (1,473)
Total Investments, Fair Value 1,218,486 992,174
U.S. agency bonds – other [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 11,683 11,682
Available-for-sale securities, Gross unrealized gains 1,173 1,407
Available-for-sale securities, Gross unrealized losses 0 0
Total Investments, Fair Value 12,856 13,089
Non-U.S. government bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 58,668 55,169
Available-for-sale securities, Gross unrealized gains 731 2,264
Available-for-sale securities, Gross unrealized losses (918) 0
Total Investments, Fair Value 58,481 57,433
Other mortgage-backed securities [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 27,629 23,167
Available-for-sale securities, Gross unrealized gains 28 901
Available-for-sale securities, Gross unrealized losses (194) 0
Total Investments, Fair Value 27,463 24,068
Corporate bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 1,317,054 1,247,260
Available-for-sale securities, Gross unrealized gains 74,091 113,386
Available-for-sale securities, Gross unrealized losses (24,505) (6,492)
Total Investments, Fair Value 1,366,640 1,354,154
Municipal bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 12,595 132,604
Available-for-sale securities, Gross unrealized gains 900 1,244
Available-for-sale securities, Gross unrealized losses 0 0
Total Investments, Fair Value $ 13,495 $ 133,848