Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies
Gains on the sales of loans	$ 859	$ 755	$ 1,198
Loans held for sale	$ 1,615	$ 94
Buildings and improvements | Minimum
Bank Premises and Equipment
Useful lives	10 years
Buildings and improvements | Maximum
Bank Premises and Equipment
Useful lives	40 years
Furniture, fixtures and equipment | Minimum
Bank Premises and Equipment
Useful lives	3 years
Furniture, fixtures and equipment | Maximum
Bank Premises and Equipment
Useful lives	15 years
Leasehold improvements | Minimum
Bank Premises and Equipment
Useful lives	5 years
Leasehold improvements | Maximum
Bank Premises and Equipment
Useful lives	30 years