Reserves for Losses and Loss Adjustment Expenses (Reconciliation of Incurred and Paid Claims to Liability for Unpaid Losses and LAE) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated loss adjustment expense, net of reinsurance	$ 449,851	$ 418,057
Reinsurance recoverable on unpaid claims	420,694	387,915
Unallocated claims adjustment expenses	10,324	10,709
Total gross liability for unpaid claims and claim adjustment expenses	880,869	816,681	$ 789,768
Commercial Accounts business unit [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated loss adjustment expense, net of reinsurance	66,708	60,511
Reinsurance recoverable on unpaid claims	35,585	27,464
Unallocated claims adjustment expenses	1,955	2,448
General Aviation and Satellite Component [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated loss adjustment expense, net of reinsurance	3,916	3,276
Reinsurance recoverable on unpaid claims	14,346	13,385
Unallocated claims adjustment expenses	27	99
Personal Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated loss adjustment expense, net of reinsurance	21,848	17,393
Reinsurance recoverable on unpaid claims	624	1,707
Unallocated claims adjustment expenses	1,885	1,625
Runoff Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated loss adjustment expense, net of reinsurance	357,379	336,877
Reinsurance recoverable on unpaid claims	370,139	345,359
Unallocated claims adjustment expenses	$ 6,457	$ 6,537