Reserves for Unpaid Losses and Loss Adjustment Expenses (Reconciliation of Incurred and Paid Claims to Liability for Unpaid Losses and LAE) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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	$ 299,068	$ 365,060
Reinsurance recoverable on unpaid claims	221,716	154,612
Unallocated claims adjustment expenses	6,463	7,428
Total gross liability for unpaid claims and claim adjustment expenses	527,247	527,100	$ 481,567
Specialty Commercial 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	228,389	275,436
Reinsurance recoverable on unpaid claims	198,802	137,975
Unallocated claims adjustment expenses	2,550	3,377
Standard Commercial 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	61,936	78,119
Reinsurance recoverable on unpaid claims	9,783	6,051
Unallocated claims adjustment expenses	2,958	3,153
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	8,743	11,505
Reinsurance recoverable on unpaid claims	13,131	10,586
Unallocated claims adjustment expenses	$ 955	$ 898