Investments (Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) During The Period Between The Market Value And Cost Of Investments Carried At Market Value, And Deferred Taxes Thereon:
Change in unrealized appreciation (depreciation), pre-tax	$ 66,625	$ (50,192)
Deferred tax benefit (expense)	(11,280)	(735)
Deferred tax benefit (expense), other-than-temporary impairment		34
Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders' equity	55,345	(50,893)
Fixed Maturity Securities [Member]
Increase (Decrease) During The Period Between The Market Value And Cost Of Investments Carried At Market Value, And Deferred Taxes Thereon:
Change in unrealized appreciation (depreciation), pre-tax	64,466	(47,947)
Fixed Maturity Securities, Other-Than-Temporary Impairment [Member]
Increase (Decrease) During The Period Between The Market Value And Cost Of Investments Carried At Market Value, And Deferred Taxes Thereon:
Change in unrealized appreciation (depreciation), pre-tax	76	(228)
Equity Securities [Member]
Increase (Decrease) During The Period Between The Market Value And Cost Of Investments Carried At Market Value, And Deferred Taxes Thereon:
Change in unrealized appreciation (depreciation), pre-tax	2,083	(2,017)
Other Invested Assets [Member]
Increase (Decrease) During The Period Between The Market Value And Cost Of Investments Carried At Market Value, And Deferred Taxes Thereon:
Change in unrealized appreciation (depreciation), pre-tax