Loss And Loss Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Unusual or Infrequent Item, or Both [Line Items]
Prior years	$ 70,399	$ 18,347
Catastrophe [Member]
Unusual or Infrequent Item, or Both [Line Items]
Loss from catastrophes	34,000	$ 59,000
Loss from catastrophes, net of reinsurance benefits	24,000
Fire [Member]
Unusual or Infrequent Item, or Both [Line Items]
Loss from catastrophes	21,000
Loss from catastrophes, net of reinsurance benefits	$ 10,000