Reserves for Insurance Claims and Claim Expenses - Reconciliation of Disclosure of Incurred and Paid Claims Development to the Liability for Unpaid Claims and Claims Adjustment Expenses (Details) - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Reinsurance recoverable on unpaid claims $ 4,939 $ 3,001 $ 1,902 $ 297
Total gross liability for unpaid claims and claim adjustment expenses 23,752 $ 12,811 $ 8,761 $ 3,001
Financial Guarantee Insurance Product Line        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Cumulative Incurred Claims and Allocated Claims Adjustment Expenses, net of Reinsurance 26,064      
Cumulative Paid Claims and Claims Adjustment Expenses, net of Reinsurance 7,609      
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance 18,455      
Reinsurance recoverable on unpaid claims 4,939      
Unallocated claims adjustment expenses 358      
Total gross liability for unpaid claims and claim adjustment expenses $ 23,752