Impaired Loans and Valuation Allowance for Loan Losses (Details Textual) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Dec. 31, 2011
Impaired Loans and Valuation Allowance for Loan Losses (Textual) [Abstract]
Newly identified TDRs	$ 0		$ 8,400,000
Impaired Loans and Valuation Allowance for Loan Losses (Additional Textual) [Abstract]
Accruing TDRs	54,800,000		54,800,000	71,600,000
Interest income on impaired loans	1,709,000	1,688,000
Construction and land development [Member]
Impaired Loans and Valuation Allowance for Loan Losses (Textual) [Abstract]
Newly identified TDRs	0		100,000
Commercial real estate [Member]
Impaired Loans and Valuation Allowance for Loan Losses (Textual) [Abstract]
Newly identified TDRs			600,000
Residential real estate [Member]
Impaired Loans and Valuation Allowance for Loan Losses (Textual) [Abstract]
Newly identified TDRs	0		3,800,000
Consumer [Member]
Impaired Loans and Valuation Allowance for Loan Losses (Textual) [Abstract]
Newly identified TDRs			$ 100,000