Reinsurance - Effect of Reinsurance on Net Premiums Written and Earned (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Net premiums written        
Direct     $ 133,526 $ 68,629
Ceded     (37,336) 0
Net premiums written     96,190 68,629
Net premiums earned        
Direct     78,900 28,626
Ceded     (1,244) 0
Net premiums earned $ 31,808 $ 12,834 $ 77,656 $ 28,626