Derivatives And Hedging (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Cash flow hedge gain (loss) reclassified to interest expense	$ (619,000)	$ (619,000)	$ (1,238,000)	$ (1,328,000)
Interest Rate Contracts [Member] | Interest Expense, Net [Member] | Fair Value Hedging [Member]
Net reduction in interest expense associated with fair value hedges	3,042,000	14,422,000	2,572,000	17,542,000
Interest Rate Contracts [Member] | Interest Expense, Net [Member] | Cash Flow Hedging [Member]
Cash flow hedge gain (loss) reclassified to interest expense	(619,000)	(619,000)	(1,238,000)	(1,328,000)
Interest Rate Contracts [Member] | Fair Value Hedging [Member]
Number of active interest rate contracts held	4		4		4
Derivative, lower fixed interest rate range	4.20%		4.20%		4.20%
Derivative, higher fixed interest rate range	7.50%		7.50%		7.50%
Notional amount of interest rate fair value hedge derivatives	119,900,000		119,900,000		120,400,000
Derivative lower variable interest rate range	0.20%		0.20%		0.30%
Derivative higher variable interest rate range	4.30%		4.30%		4.40%
Net reduction in interest expense associated with fair value hedges	1,800,000	1,700,000	3,600,000	3,200,000
Recognized gain associated with hedge ineffectiveness		300,000		600,000
Interest Rate Contracts [Member] | Cash Flow Hedging [Member]
Number of active interest rate contracts held	3		3		2
Notional amount of interest rate cash flow hedge derivatives	27,400,000		27,400,000		11,800,000
Cash flow hedges of interest rate risk maturities through			September 2017
Derivative, lower fixed interest rate range	2.30%		2.30%		2.30%
Derivative, higher fixed interest rate range	5.00%		5.00%		5.00%
Fair value of derivatives assets included in net other assets	100,000		100,000		100,000
Fair value of derivative liabilities included in net other liabilities	200,000		200,000		100,000
Accumulated loss from derivative instruments	10,700,000		10,700,000		11,700,000
Cash flow hedge gain (loss) to be amortized within 12 months			$ 2,600,000