Allowance for Loan Losses (Details 4) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Summary of Non-accrual Loans
Total, Non- Accrual Status	$ 33,748	$ 25,768
Commercial and Agriculture [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	2,793	940
Commercial Real Estate [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	19,137	15,346
Residential Real Estate [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	10,408	8,915
Real estate - construction [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	1,355	567
Consumer [Member]
Summary of Non-accrual Loans
Total, Non- Accrual Status	$ 55