v2.4.0.6
Net Investment Income (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Schedule of Investment Income, Reported Amounts, by Category [Line Items]        
Gross investment income $ 16,544 $ 13,388 $ 31,197 $ 27,834
Less: Investment expenses and interest expense on securities sold under agreement to repurchase 200 221 335 475
Net investment income 16,344 13,167 30,862 27,359
Fixed maturities
       
Schedule of Investment Income, Reported Amounts, by Category [Line Items]        
Gross investment income 16,059 12,302 29,723 25,976
Equity securities
       
Schedule of Investment Income, Reported Amounts, by Category [Line Items]        
Gross investment income 100 120 498 286
Cash and cash equivalents
       
Schedule of Investment Income, Reported Amounts, by Category [Line Items]        
Gross investment income $ 385 $ 966 $ 976 $ 1,572