Loss And Loss Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unusual or Infrequent Item, or Both [Line Items]
Prior year claims and claim adjustment expense	$ 93,096	$ 54,431	$ 85,369
Catastrophe [Member]
Unusual or Infrequent Item, or Both [Line Items]
Prior year claims and claim adjustment expense	93,100	54,400	85,400
Pre-tax catastrophe losses	289,000	168,000	$ 27,000
Pre-tax catastrophe losses, net of reinsurance benefits	$ 67,000	$ 79,000