Investment Securities (Other Disclosures) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
FHLB stock	$ 6,300,000		$ 6,300,000		$ 6,300,000
FRBR stock	3,700,000		3,700,000		3,700,000
Investment securities portfolio available as lendable collateral	378,400,000		378,400,000
Book value of securities sold	21,400,000	252,700,000	134,100,000	282,900,000
Gain on securities sold	(33,000)	7,393,000	1,923,000	7,308,000
Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities portfolio pledged as collateral	93,400,000		93,400,000
Retail repurchase agreements [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities portfolio pledged as collateral	14,500,000		14,500,000
Federal Reserve Bank of Richmond [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities portfolio pledged as collateral	4,000,000		4,000,000
Others [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities portfolio pledged as collateral	$ 2,100,000		$ 2,100,000