Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010
Accumulated other comprehensive income (loss), net of tax	$ (32,527)	[1]	$ (36,529)	[2]	$ (24,333)	[1]
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income (loss)	(53,453)		(59,993)		(41,121)
Deferred tax expense (benefit)	(20,926)		(23,464)		(16,788)
Accumulated other comprehensive income (loss), net of tax	(32,527)		(36,529)		(24,333)
Unrealized gains on investment securities available for sale [Member]
Accumulated other comprehensive income (loss)	28,830		23,195		41,026
Deferred tax expense (benefit)	11,340		9,143		15,427
Accumulated other comprehensive income (loss), net of tax	17,490		14,052		25,599
Funded status of defined benefit plan [Member]
Accumulated other comprehensive income (loss)	(68,752)		(73,696)		(67,884)
Deferred tax expense (benefit)	(26,923)		(28,859)		(26,583)
Accumulated other comprehensive income (loss), net of tax	(41,829)		(44,837)		(41,301)
Unrealized loss on cash flow hedges [Member]
Accumulated other comprehensive income (loss)	(13,531)		(9,492)		(14,263)
Deferred tax expense (benefit)	(5,343)		(3,748)		(5,632)
Accumulated other comprehensive income (loss), net of tax	$ (8,188)		$ (5,744)		$ (8,631)

[1] Unaudited

[2] Derived from 2010 Annual Report on Form 10-K.