Capital Purchase Program (Details) (USD $)	12 Months Ended
	Dec. 31, 2009	Mar. 31, 2013
Capital Purchase Program [Abstract]
Preferred stock issued under capital repurchase program (in shares)	22,000
Warrants issued under capital repurchase program (in shares)		208,202
Exercise price of warrants (in dollars per share)	$ 15.85
Class of warrant or right outstanding (in shares)		104,101