Allowance For Loan Losses And Credit Quality Of Financing Receivables - Loans Which The Accrual Of Interest Has Been Discontinued (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans for which accrual of interest has been discounted	$ 19,758	$ 6,020
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans for which accrual of interest has been discounted	291	20
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans for which accrual of interest has been discounted	0	105
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans for which accrual of interest has been discounted	15,199	4,314
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans for which accrual of interest has been discounted	$ 4,268	$ 1,581