Derivatives And Hedging (Narrative) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2012 contracts	Dec. 31, 2011 contracts
Derivatives And Hedging [Line Items]
Accumulated loss from derivative instruments	$ 8,827,000	$ 10,016,000
Interest Rate Contracts [Member] | Cash Flow Hedges [Member]
Derivatives And Hedging [Line Items]
Number of active interest rate contracts held	3	3
Notional amount of interest rate cash flow hedge derivatives	26,800,000	27,100,000
Interest rate contracts maturities through	September 2017	September 2017
Derivative, lower fixed interest rate range	2.30%	2.30%
Derivative, higher fixed interest rate range	5.00%	5.00%
Cash flow hedge gain (loss) to be amortized within 12 months	(2,900,000)
Interest Rate Contracts [Member] | Fair Value Hedges [Member]
Derivatives And Hedging [Line Items]
Number of active interest rate contracts held	4	4
Notional amount of interest rate fair value hedge derivatives	$ 118,700,000	$ 119,300,000
Interest rate contracts maturities through	October 2017	October 2017
Derivative, lower fixed interest rate range	4.20%	4.20%
Derivative, higher fixed interest rate range	7.50%	7.50%
Derivative, lower variable interest rate range	0.50%	0.50%
Derivative, higher variable interest rate range	4.40%	4.40%