v2.4.0.8
Fair Value Measurements - Fair Value Hierarchy (Details) (USD $)
In Thousands, unless otherwise specified
0 Months Ended
Mar. 31, 2014
Dec. 31, 2013
Mar. 31, 2014
Investments in limited partnerships [Member]
Dec. 31, 2013
Investments in limited partnerships [Member]
Mar. 31, 2014
Other [Member]
Dec. 31, 2013
Other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. treasury bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. treasury bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. agency bonds – mortgage-backed [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. agency bonds – mortgage-backed [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. agency bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
U.S. agency bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Non-U.S. government bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Non-U.S. government bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Other mortgage-backed securities [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Other mortgage-backed securities [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Municipal bonds – auction rate [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Municipal bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Municipal bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. treasury bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. treasury bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. agency bonds – mortgage-backed [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. agency bonds – mortgage-backed [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. agency bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
U.S. agency bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Non-U.S. government bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Non-U.S. government bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Other mortgage-backed securities [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Other mortgage-backed securities [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Municipal bonds – auction rate [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Municipal bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Municipal bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. treasury bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. treasury bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. agency bonds – mortgage-backed [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. agency bonds – mortgage-backed [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. agency bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
U.S. agency bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Non-U.S. government bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Non-U.S. government bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Other mortgage-backed securities [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Other mortgage-backed securities [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Municipal bonds – auction rate [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Municipal bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Municipal bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Fixed Maturities [Member]
securities
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Fixed Maturities [Member]
securities
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. treasury bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. treasury bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. agency bonds – mortgage-backed [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. agency bonds – mortgage-backed [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. agency bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
U.S. agency bonds – other [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Non-U.S. government bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Non-U.S. government bonds [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Other mortgage-backed securities [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Other mortgage-backed securities [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Corporate bonds [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Municipal bonds – auction rate [Member]
Mar. 31, 2014
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Municipal bonds – other [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Total Fair Value [Member]
Municipal bonds – other [Member]
Jan. 15, 2014
Junior subordinated debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                                                                                                                                                          
Extinguishment of debt, amount                                                                                                                                                         $ 126,381
Fixed maturities, fair value                 17,135 17,209 0 0 0 0 0 0 0 0 0 0 0 0 0     0 0 1,235,470 1,262,655 8,196 8,108 73,965 73,212 44,368 33,444 1,725,768 1,606,700 99,170 63,917 61,569     0 0 0 0 0 0 0 0 0 0 0 0 0 0 0         17,135 17,209 1,235,470 1,262,655 8,196 8,108 73,965 73,212 44,368 33,444 1,725,768 1,606,700 99,170 63,917 61,569  
Other investments, fair value             0 0                               0 0                               5,773 5,092                               5,773 5,092                                    
Total             17,135 17,209                               3,151,684 3,144,858                               5,773 5,092                               3,174,592 3,167,159                                    
Percentage of total assets             0.40% 0.40%                               64.70% 66.70%                               0.10% 0.10%                               65.20% 67.20%                                    
Assets, valued by third party, percentage                                                                                                                       99.90% 95.30%                                
Assets, valued using market approach, percentage                                                                                                                       0.10% 4.70%                                
Assets, valued using market approach, number                                                                                                                       2 5                                
Assets, valued using market approach, amount                                                                                                                       3,411 150,298                                
Other investments $ 5,773 $ 5,092 $ 4,773 $ 4,092 $ 1,000 $ 1,000                                                                                                                                              
Other investments, percent of assets     0.20%