Reinsurance - Amounts Ceded Related to 2016 QSR Transaction (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Ceded Credit Risk [Line Items]        
Ceded premiums written $ (6,886) $ 0 $ (11,527) $ 0
Ceded premiums earned (6,316) $ 0 (10,529) $ 0
Third-Party Reinsurers        
Ceded Credit Risk [Line Items]        
Ceded risk-in-force 2,403,027   2,403,027  
Ceded premiums written (12,034)   (22,326)  
Ceded premiums earned (11,463)   (21,328)  
Ceded claims and claims expenses 342   610  
Ceding commission written 2,407   4,465  
Ceding commission earned 2,275   4,340  
Profit commission $ 6,536   $ 12,187