On-Balance Sheet Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 days	Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 70,000,000	$ 70,000,000
Fair value of derivatives	62,000
Interest rate swaps, interest expense decreased	1,722,000	1,646,000
Derivative, collateral, right to reclaim cash	1,210,000	1,210,000
Rate lock period (days)	60
Customer Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	293,794,000
Offsetting Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	293,794,000
Equity-Indexed Certificates Of Deposit Asset [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	158,164,000	74,171,000
Equity-Indexed Certificates Of Deposit Liability [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	158,164,000	74,171,000
Customer Interest Rate Contracts [Member] | Offsetting Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 247,292,000