Derivatives And Hedging (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended			9 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Interest Rate Contracts [Member] Interest Expense, Net [Member] Fair Value Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Interest Expense, Net [Member] Fair Value Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Interest Expense, Net [Member] Fair Value Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Interest Expense, Net [Member] Fair Value Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Interest Expense, Net [Member] Cash Flow Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Interest Expense, Net [Member] Cash Flow Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Interest Expense, Net [Member] Cash Flow Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Interest Expense, Net [Member] Cash Flow Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Fair Value Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Fair Value Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Fair Value Hedging [Member]	Sep. 30, 2010 Interest Rate Contracts [Member] Fair Value Hedging [Member]	Dec. 31, 2010 Interest Rate Contracts [Member] Fair Value Hedging [Member]	Sep. 30, 2011 Interest Rate Contracts [Member] Cash Flow Hedging [Member]	Dec. 31, 2010 Interest Rate Contracts [Member] Cash Flow Hedging [Member]	Sep. 30, 2011 Interest Expense, Net [Member]	Sep. 30, 2010 Interest Expense, Net [Member]	Sep. 30, 2011 Interest Expense, Net [Member]	Sep. 30, 2010 Interest Expense, Net [Member]
Derivatives And Hedging [Line Items]
Number of active interest rate contracts held													4		4		4	3	2
Notional amount of interest rate cash flow hedge derivatives																		$ 27,300,000	$ 11,800,000
Cash flow hedges of interest rate risk maturities through															October 2017			September 2017	September 2017
Derivative, lower fixed interest rate range													4.20%		4.20%		4.20%	2.30%	2.30%
Derivative, higher fixed interest rate range													7.50%		7.50%		7.50%	5.00%	5.00%
Fair value of derivatives assets included in net other assets																		40,000	90,000
Fair value of derivative liabilities included in net other liabilities																		700,000	100,000
Accumulated loss from derivative instruments																		10,600,000	11,700,000
Cash flow hedge gain (loss) reclassified to interest expense	(654,000)	(619,000)	(1,892,000)	(1,947,000)					(654,000)	(619,000)	(1,892,000)	(1,947,000)
Cash flow hedge gain (loss) to be amortized within 12 months																		2,600,000
Notional amount of interest rate fair value hedge derivatives													119,600,000		119,600,000		120,400,000
Derivative, lower variable interest rate range													0.30%		0.30%		0.30%
Derivative, higher variable interest rate range													4.30%		4.30%		4.40%
Net reduction in interest expense associated with fair value hedges					4,577,000	2,232,000	7,149,000	19,774,000					1,800,000	1,500,000	5,300,000	4,700,000
Recognized gain associated with hedge ineffectiveness																					$ 328,000		$ 879,000