Statutory Information - Schedule of Statutory Net Loss, Surplus, Contingency Reserve and Risk-to-Capital Ratio (Details) - Combined
$ in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2016
USD ($)
Dec. 31, 2015
USD ($)
Statutory Accounting Practices [Line Items]    
Statutory net loss $ (23,808) $ (52,322)
Statutory surplus 367,987 391,422
Contingency reserve $ 72,014 $ 32,564
Risk-to-Capital 11.7 8.7