Schedule IV - Reinsurance (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Premium Earned:      
Gross amount $ 494,643 $ 461,367 $ 434,022
Ceded to other companies 145,562 140,477 76,685
Assumed from other companies   327 3,204
Net premiums earned $ 349,081 $ 321,217 $ 360,541
Percentage of amount assumed to net 0.00% 0.10% 0.89%
Property, Liability and Casualty Insurance Segment [Member]      
Premium Earned:      
Gross amount $ 494,643 $ 461,367 $ 434,022
Ceded to other companies 145,562 140,477 76,685
Assumed from other companies   327 3,204
Net premiums earned $ 349,081 $ 321,217 $ 360,541
Percentage of amount assumed to net 0.00% 0.10% 0.89%