Fair Value (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Amortization of premiums on securities included in interest income			$ 35,000
Accretion of discounts on securities included in interest income			11,000
Credit losses on securities included in income			161,000
Principal amount of impaired commercial and commercial real estate loans	53,200,000		53,200,000		49,400,000
Valuation allowance	11,500,000		11,500,000		11,300,000
Other real estate owned property write-downs	11,800,000
Provision for loan losses expensed			4,000,000		7,500,000
Interest income for residential loans held for sale	34,000	51,000	65,000	100,000
Past due period of mortgage loans held for sale, days	90		90
States And Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities transferred to Level 3					1,300,000
Other Real Estate Owned And Other Repossessed Property [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net carrying amount other real estate owned and other repossessed property	32,900,000		32,900,000
Outstanding balance other real estate owned and other repossessed property	49,000,000		49,000,000
Valuation allowance	$ 16,100,000		$ 16,100,000
Maximum [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Appraisals discount rate			45.00%
Minimum [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Appraisals discount rate			0.00%