Debt And Equity Securities (Change In Credit Portion Of The Other-Than-Temporary Impairments Recognized In Earnings On Debt Securities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Debt And Equity Securities [Abstract]
Credit loss on debt securities held at beginning of period	$ 34,176	$ 25,108
Addition to credit loss for which an other-than-temporary impairment was previously recognized	2,602	297
Addition to credit loss for which an other-than-temporary impairment was not previously recognized
Credit loss on debt securities held at end of period	$ 36,778	$ 25,405