Reserves for Insurance Claims and Claims Expenses - Reconciliation of Reserve Balances for Insurance Claims Expense (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]    
Beginning balance $ 3,001 $ 679
Less reinsurance recoverables 297 0
Beginning balance, net of reinsurance recoverables 2,704 679
Claims incurred:    
Current year 2,331 1,113
Prior years (323) (185)
Total claims and claims expenses incurred 2,008 928
Claims and claim expenses paid:    
Current year 0 0
Prior years 563 132
Total claims and claim expenses paid 563 132
Ending balance, net of reinsurance recoverables 4,149 1,475
Add reinsurance recoverables 899 0
Reserve at end of period, net of reinsurance recoverables $ 5,048 $ 1,475