Reserves for Unpaid Losses and Loss Adjustment Expenses (Causes for Prior Accident Year Reserve Development by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	$ 3,555	$ 10,421
Continuing Operations
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	3,555	10,421
Standard Commercial Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	997	(429)
General Aviation and Satellite Component [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	300
Workers Compensation Business Unit [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	100
Personal Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	523	1,573
Runoff Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total unfavorable (favorable) net prior year development	$ 2,035	$ 9,277