Capital Purchase Program and Stock Offerings (Details) (USD $)					0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Aug. 31, 2009	Jan. 30, 2009	Dec. 23, 2009 Series A Cumulative Perpetual Preferred Stock [Member]	Jan. 30, 2009 Series A Cumulative Perpetual Preferred Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Preferred stock issued under capital repurchase program (in shares)						22,000
Preferred stock, par value (in dollars per share)						$ 2.5
Liquidation preference per share (in dollars per shares)						$ 1,000
Warrants issued under capital repurchase program (in shares)			104,101	208,202
Common stock, par value (in dollars per share)	$ 2.5	$ 2.5		$ 2.5
Exercise price of warrants (in dollars per share)				$ 15.85
Shares redeemed during period (in shares)					22,000