Investments (Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	$ (145,079)	$ 97,939	$ (10,583)	$ 164,564
Deferred tax benefit (expense)	21,344	(9,849)	(4,356)	(21,129)
Deferred tax benefit (expense), other-than-temporary impairment	1		(3,407)
Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders' equity	(123,734)	88,090	(18,346)	143,435
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	(144,172)	93,403	(17,910)	157,869
Fixed Maturity Securities, Other-Than-Temporary Impairment [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	(477)	5	9,207	81
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	$ (430)	$ 4,531	$ (1,880)	$ 6,614