Other Comprehensive (Loss) Income (Schedule Of Changes In Accumulated Other Comprehensive Loss After Tax) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Total Accumulated Other Comprehensive Income (Loss), Balance	$ (5,719)	$ (19,816)	$ (60,931)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment		(69,536)
Net change	(56,722)	14,097	49,720
Total Accumulated Other Comprehensive Income (Loss), Balance	(62,441)	(5,719)	(19,816)
Unrealized Gains and Losses on AFS Securities [Member]
Total Accumulated Other Comprehensive Income (Loss), Balance	14,930	9,623	(32,725)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment		(32,725)
Net change	(18,161)	5,307	42,348
Total Accumulated Other Comprehensive Income (Loss), Balance	(3,231)	14,930	9,623
Non-credit Impairment Losses on Securities[Member]
Total Accumulated Other Comprehensive Income (Loss), Balance	(1,543)	(7,612)
Cumulative effect of adoption of a new accounting principle (ASC Topic 320)				(8,605)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment		(8,605)
Net change	(15,023)	6,069	993
Total Accumulated Other Comprehensive Income (Loss), Balance	(16,566)	(1,543)	(7,612)
Unrealized Gains And Losses On Derivatives [Member]
Total Accumulated Other Comprehensive Income (Loss), Balance	(708)	(2,716)	(5,000)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment		(5,000)
Net change	(12,377)	2,008	2,284
Total Accumulated Other Comprehensive Income (Loss), Balance	(13,085)	(708)	(2,716)
Pension Benefit Adjustment [Member]
Total Accumulated Other Comprehensive Income (Loss), Balance	(18,398)	(19,111)	(23,206)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment		(23,206)
Net change	(11,161)	713	4,095
Total Accumulated Other Comprehensive Income (Loss), Balance	(29,559)	(18,398)	(19,111)
Accumulated Other Comprehensive Loss [Member]
Cumulative effect of adoption of a new accounting principle (ASC Topic 320)		14,097		(8,605)
Total Accumulated Other Comprehensive Income (Loss), Balance After Adjustment			(8,605)
Net change	$ (56,722)	$ 14,097	$ 49,720