Losses And Loss Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unusual or Infrequent Item, or Both [Line Items]
Prior year claims and claim adjustment expense	$ (85,369)	$ (12,658)	$ 3,193
Catastrophe [Member]
Unusual or Infrequent Item, or Both [Line Items]
Pre-tax catastrophe losses	$ 27,000	$ 19,000	$ 11,000