Loans and the Allowance for Loan Losses - Information Pertaining to Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	$ 712	$ 1,141	$ 712	$ 1,141
With no required reserve recorded, Average Carrying Value	717	1,148	722	1,154
With no required reserve recorded, Unpaid Principal Balance	911	1,393	911	1,393
With no required reserve recorded, Interest Income Recognized	1		3	1
Carrying Value	712	1,141	712	1,141
Average Carrying Value	717	1,148	722	1,154
Unpaid Principal Balance	911	1,393	911	1,393
Interest Income Recognized	1		3	1
Commercial and Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value		17		17
With no required reserve recorded, Average Carrying Value		20		22
With no required reserve recorded, Unpaid Principal Balance		17		17
With no required reserve recorded, Interest Income Recognized				1
Carrying Value		17		17
Average Carrying Value		20		22
Unpaid Principal Balance		17		17
Interest Income Recognized				1
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value		213		213
With no required reserve recorded, Average Carrying Value		213		213
With no required reserve recorded, Unpaid Principal Balance		227		227
Carrying Value		213		213
Average Carrying Value		213		213
Unpaid Principal Balance		227		227
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	616	845	616	845
With no required reserve recorded, Average Carrying Value	620	848	625	851
With no required reserve recorded, Unpaid Principal Balance	778	1,051	778	1,051
With no required reserve recorded, Interest Income Recognized	1		2
Carrying Value	616	845	616	845
Average Carrying Value	620	848	625	851
Unpaid Principal Balance	778	1,051	778	1,051
Interest Income Recognized	1		2
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	96	66	96	66
With no required reserve recorded, Average Carrying Value	97	67	97	68
With no required reserve recorded, Unpaid Principal Balance	133	98	133	98
With no required reserve recorded, Interest Income Recognized			1
Carrying Value	96	66	96	66
Average Carrying Value	97	67	97	68
Unpaid Principal Balance	$ 133	$ 98	133	$ 98
Interest Income Recognized			$ 1