Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011
Accumulated other comprehensive income (loss), net of tax	$ (62,407)	[1]	$ (66,574)	[2]	$ (29,451)	[1]
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss)	(102,541)		(109,404)		(48,361)
Deferred tax expense (benefit)	(40,134)		(42,830)		(18,910)
Accumulated other comprehensive income (loss), net of tax	(62,407)		(66,574)		(29,451)
Unrealized Gains on Investment Securities Available for Sale
Accumulated other comprehensive income (loss)	28,155		26,565		31,839
Deferred tax expense (benefit)	11,082		10,450		12,528
Accumulated other comprehensive income (loss), net of tax	17,073		16,115		19,311
Funded Status of Defined Benefit Plan
Accumulated other comprehensive income (loss)	(119,676)		(125,255)		(70,400)
Deferred tax expense (benefit)	(46,865)		(49,049)		(27,568)
Accumulated other comprehensive income (loss), net of tax	(72,811)		(76,206)		(42,832)
Unrealized Loss on Cash Flow Hedges
Accumulated other comprehensive income (loss)	(11,020)		(10,714)		(9,800)
Deferred tax expense (benefit)	(4,351)		(4,231)		(3,870)
Accumulated other comprehensive income (loss), net of tax	$ (6,669)		$ (6,483)		$ (5,930)

[1] Unaudited

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