Allowance for 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	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Allowance For Loan And Lease Losses And Unfunded Loan Commitments And Letters Of Credit
Beginning balance	$ 3,130	$ 2,705
Allowance for Loan and Lease Losses, Net Changes In Unfunded Commitments and Letters Of Credit Allowance	1,200	850
Ending balance	$ 4,330	$ 3,555