Property and Casualty Unpaid Claims and Claim Expenses - Reconciliation of Net Incurred and Paid Claims (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Gross reserves, end of year	$ 442,854	$ 396,714
Property and Casualty
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	246,499
Reinsurance Recoverables, Including Reinsurance Premium Paid	120,506
Unallocated claims adjustment expenses	19,971
Total other than short duration and unallocated claims adjustment expenses	75,849
Property and Casualty | Homeowners
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	35,480
Reinsurance Recoverables, Including Reinsurance Premium Paid	12,394
Property and Casualty | Auto liability
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	203,180
Reinsurance Recoverables, Including Reinsurance Premium Paid	100,866
Property and Casualty | Auto physical damage
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	4,947
Property and Casualty | Other short duration lines
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	2,892
Reinsurance Recoverables, Including Reinsurance Premium Paid	7,246
Property and Casualty | Insurance lines other than short duration
Insurance lines other than short duration	$ 55,878