Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Accumulated other comprehensive income (loss), net of tax	$ (51,986)	[1]	$ (66,574)	[2]	$ (32,527)	[1]
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss)	(85,150)		(109,404)		(53,453)
Deferred tax expense (benefit)	(33,164)		(42,830)		(20,926)
Accumulated other comprehensive income (loss), net of tax	(51,986)		(66,574)		(32,527)
Unrealized Gains on Investment Securities Available for Sale
Accumulated other comprehensive income (loss)	42,907		26,565		28,830
Deferred tax expense (benefit)	17,019		10,450		11,340
Accumulated other comprehensive income (loss), net of tax	25,888		16,115		17,490
Funded Status of Defined Benefit Plan
Accumulated other comprehensive income (loss)	(116,887)		(125,255)		(68,752)
Deferred tax expense (benefit)	(45,773)		(49,049)		(26,923)
Accumulated other comprehensive income (loss), net of tax	(71,114)		(76,206)		(41,829)
Unrealized Loss on Cash Flow Hedges
Accumulated other comprehensive income (loss)	(11,170)		(10,714)		(13,531)
Deferred tax expense (benefit)	(4,410)		(4,231)		(5,343)
Accumulated other comprehensive income (loss), net of tax	$ (6,760)		$ (6,483)		$ (8,188)

[1] Unaudited

[2] Derived from 2011 Annual Report on Form 10-K.