On-Balance Sheet Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 D	Dec. 31, 2011	Mar. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 70,000,000		$ 70,000,000
Fair value of derivatives	26,000
Derivative, collateral, right to reclaim cash	1,210,000	1,210,000
Rate lock period (in days)	60
Customers Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	306,195,000		261,566,000
Offsetting Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	306,195,000	293,794,000
Equity-Indexed Certificates Of Deposit Asset [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	167,287,000		99,412,000
Equity-Indexed Certificates Of Deposit Liability [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 167,287,000	$ 158,164,000