Allowance for Loan Losses (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of Non-accrual Loans
Total, Non- Accrual Status	$ 27,152	$ 25,768
Commercial and agriculture [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	576	940
Commercial Real Estate [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	15,287	15,346
Residential Real Estate [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	10,668	8,915
Real Estate Construction [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	610	567
Consumer [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	$ 11