Loans and Allowance for Loan Losses (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Summary of nonperforming and restructured assets
Past due over 90 days and still accruing	$ 1,403	$ 798	$ 1,166
Nonaccrual	20,702	21,187	22,469
Restructured	18,089	1,041	344
Total nonperforming and restructured loans	40,194	23,026	23,979
Other real estate owned and repossessed assets	10,223	16,640	15,501
Total nonperforming and restructured assets	$ 50,417	$ 39,666	$ 39,480
Nonperforming and restructured loans to total loans	1.31%	0.76%	0.84%
Nonperforming and restructured assets to total assets	0.89%	0.71%	0.75%