v2.4.0.8
Investments - Schedule of Investments Reconciliation (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost $ 3,096,675 $ 3,127,792
Other Investments, Original or amortized cost 5,083 4,522
Total investments, Original or amortized cost 3,101,758 3,132,314
Available-for-sale securities, Gross unrealized gains 118,334 100,648
Other investments, Gross unrealized gains 690 570
Investments, Gross unrealized gains 119,024 101,218
Available-for-sale securities, Gross unrealized losses (46,190) (66,373)
Other investments, Gross unrealized losses 0 0
Investments, Gross unrealized losses (46,190) (66,373)
Fair value 3,168,819 3,162,067
Other investments 5,773 5,092
Total investments 3,174,592 3,167,159
U.S. treasury bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 16,616 16,622
Available-for-sale securities, Gross unrealized gains 519 587
Available-for-sale securities, Gross unrealized losses 0 0
Fair value 17,135 17,209
U.S. agency bonds – mortgage-backed [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 1,257,045 1,292,032
Available-for-sale securities, Gross unrealized gains 12,632 11,727
Available-for-sale securities, Gross unrealized losses (34,207) (41,104)
Fair value 1,235,470 1,262,655
U.S. agency bonds – other [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 7,208 7,207
Available-for-sale securities, Gross unrealized gains 988 901
Available-for-sale securities, Gross unrealized losses 0 0
Fair value 8,196 8,108
Non-U.S. government bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 70,806 70,377
Available-for-sale securities, Gross unrealized gains 3,490 3,547
Available-for-sale securities, Gross unrealized losses (331) (712)
Fair value 73,965 73,212
Other mortgage-backed securities [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 43,952 33,676
Available-for-sale securities, Gross unrealized gains 416 0
Available-for-sale securities, Gross unrealized losses 0 (232)
Fair value 44,368 33,444
Corporate bonds [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 1,638,912 1,546,578
Available-for-sale securities, Gross unrealized gains 98,508 82,952
Available-for-sale securities, Gross unrealized losses (11,652) (22,830)
Fair value 1,725,768 1,606,700
Municipal bonds – auction rate [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost   99,170
Available-for-sale securities, Gross unrealized gains   0
Available-for-sale securities, Gross unrealized losses   0
Fair value   99,170
Municipal bonds – other [Member]
    
Schedule of Investments [Line Items]    
Fixed Maturities, available-for-sale, Amortized cost 62,136 62,130
Available-for-sale securities, Gross unrealized gains 1,781 934
Available-for-sale securities, Gross unrealized losses 0 (1,495)
Fair value $ 63,917 $ 61,569