Allowance for Noncovered Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Changes in the Allowance for Unfunded Commitments and Letters of Credit) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance For Loan And Lease Losses And Unfunded Loan Commitments And Letters Of Credit
Beginning balance	$ 1,535	$ 1,165	$ 775
Net changes in the allowance for unfunded commitments and letters of credit	380	370	390
Ending balance	$ 1,915	$ 1,535	$ 1,165