Losses And Loss Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Unusual or Infrequent Item, or Both [Line Items]
Prior years claims and claim adjustment expense	$ 4,124	$ 39,802
Catastrophe [Member]
Unusual or Infrequent Item, or Both [Line Items]
Pre-tax catastrophe losses	$ 30,000	$ 8,000