Comprehensive Income (Schedule Of Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Comprehensive Income [Abstract]
Net gains arising during the period, Before Tax	$ 6,233	$ 2,983
Net gains arising during the period, Tax Effect	(2,007)	(1,170)
Net gains arising during the period, After Tax	4,226	1,813
Less reclassification adjustment for losses (gains) included in net income, Before Tax	157	(2,679)
Less reclassification adjustment for losses (gains) included in net income, Tax Effect	(62)	1,000
Less reclassification adjustment for losses (gains) included in net income, After Tax	95	(1,679)
Net change, Unrealized gains and losses on available for sale securities, Before Tax	6,390	304
Net change, Unrealized gains and losses on available for sale securities, Tax Effect	(2,069)	(170)
Total	4,321	134
Net change in non-credit impairment losses on securities, Before Tax	11,286	175
Net change in non-credit impairment losses on securities, Tax Effect	(4,216)	(73)
Net change in non-credit impairment losses on securities, After Tax	7,070	102
Less reclassification adjustment for credit impairment losses included in net income, Before Tax	(303)	669
Less reclassification adjustment for credit impairment losses included in net income, Tax Effect	113	(251)
Less reclassification adjustment for credit impairment losses included in net income, After Tax	(190)	418
Net change, Non-credit impairment losses on securities available for sale and held to maturity, Before Tax	10,983	844
Net change, Non-credit impairment losses on securities, Tax Effect	(4,103)	(324)
Total	6,880	520
Net gains arising during the period, Before Tax	1,549	1,434
Net gains arising during the period, Tax Effect	(650)	(602)
Net gains arising during the period, After Tax	899	832
Less reclassification adjustment for losses included in net income, Before Tax	1,392	577
Less reclassification adjustment for losses included in net income, Tax Effect	(584)	(242)
Less reclassification adjustment for losses included in net income, After Tax	808	335
Net change, Unrealized gains and losses on derivatives, Before Tax	2,941	2,011
Net change, Unrealized gains and losses on derivatives, Tax Effect	(1,234)	(844)
Total	1,707	1,167
Pension benefit adjustment, Before Tax	759	503
Pension benefit adjustment, Tax Effect	(318)	(211)
Pension benefit adjustment, After Tax	441	292
Total other comprehensive income, Before Tax	21,073	3,662
Total other comprehensive income, Tax Effect	(7,724)	(1,549)
Total other comprehensive income, After Tax	$ 13,349	$ 2,113