Debt And Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Debt And Shareholders' Equity [Line Items]
Beginning balance			$ (592,084)	$ (461,296)
Net realized and unrealized holding losses, net of income tax expense/benefit			29,045	(36,060)
Reclassification for net losses included in earnings, net of income tax benefit	821	4,636	6,619	6,590
Noncredit-related impairment losses on securities not expected to be sold, net of income tax benefit			(15,303)	(729)
Accretion of securities with noncredit-related impairment losses not expected to be sold, net of income tax expense/benefit			532	99
Net unrealized losses, net of reclassification to earnings and income tax benefit			(4,956)	(13,095)
Other comprehensive income (loss)	(4,580)	(5,328)	15,937	(43,195)
Ending balance	(576,147)	(504,491)	(576,147)	(504,491)
Net realized and unrealized holding gains, income tax expense (benefit)			17,775	(22,217)
Reclassification for net losses included in earnings, income tax benefit			4,318	4,128
Noncredit-related impairment losses on securities not expected to be sold, income tax benefit			9,479	452
Accretion of securities with noncredit-related impairment losses not expected to be sold, income tax expense			349	61
Net unrealized losses, reclassification to earnings			8,493	23,105
Net unrealized losses, income tax benefit			3,231	8,335
Net Unrealized Gains (Losses) On investments And Other [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			(546,763)	(456,264)
Net realized and unrealized holding losses, net of income tax expense/benefit			29,045	(36,060)
Reclassification for net losses included in earnings, net of income tax benefit			6,619	6,590
Noncredit-related impairment losses on securities not expected to be sold, net of income tax benefit			(15,303)	(729)
Accretion of securities with noncredit-related impairment losses not expected to be sold, net of income tax expense/benefit			532	99
Other comprehensive income (loss)			20,893	(30,100)
Ending balance	(525,870)	(486,364)	(525,870)	(486,364)
Net Unrealized Gains (Losses) On Derivative Instruments [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			9,404	30,702
Net unrealized losses, net of reclassification to earnings and income tax benefit			(4,956)	(13,095)
Other comprehensive income (loss)			(4,956)	(13,095)
Ending balance	4,448	17,607	4,448	17,607
Pension And Post-Retirement [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			(54,725)	(35,734)
Other comprehensive income (loss)			0	0
Ending balance	$ (54,725)	$ (35,734)	$ (54,725)	$ (35,734)