v3.3.1.900
Reserve for Loss and Loss Adjustment Expenses (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2015
Dec. 31, 2014
Insurance [Abstract]          
Reserve for reported loss and LAE       $ 1,411,712 $ 1,241,132
Reserve for losses incurred but not reported       1,098,389 1,030,160
Reserve for loss and LAE $ 2,271,292 $ 1,957,835 $ 1,740,281 $ 2,510,101 $ 2,271,292
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]          
Gross loss and LAE reserves, January 1 2,271,292 1,957,835 1,740,281    
Less: reinsurance recoverable on unpaid losses, January 1 75,873 84,036 110,858    
Net loss and LAE reserves, January 1 2,195,419 1,873,799 1,629,423    
Net incurred losses related to Current year 1,558,704 1,479,425 1,351,043    
Net incurred losses related to Prior years 74,866 18,846 (1,413)    
Net incurred losses 1,633,570 1,498,271 1,349,630    
Net paid losses related to Current year (457,517) (430,394) (517,606)    
Net paid losses related to Prior years (892,840) (705,397) (598,490)    
Net paid losses (1,350,357) (1,135,791) (1,116,096)    
Effect of foreign exchange movements (39,779) (40,860) 10,842    
Net loss and LAE reserves, December 31 2,438,853 2,195,419 1,873,799    
Reinsurance recoverable on unpaid losses, December 31 71,248 75,873 84,036    
Gross loss and LAE reserves, December 31 $ 2,510,101 $ 2,271,292 $ 1,957,835    
Percentage of prior year net loss and loss adjustment expense reserves 3.30% 1.00% 0.10%