Loans and the Allowance for Loan Losses - Non-performing Loans Disaggregated by Loan Category (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment Past Due [Line Items]
Troubled debt restructurings	$ 133,000	$ 150,000
Non-Performing Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	1,028,000	1,148,000
Troubled debt restructurings	133,000	150,000
Total	1,161,000	1,298,000
Non-Performing Loans | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	801,000	918,000
Troubled debt restructurings	116,000	121,000
Total	917,000	1,039,000
Non-Performing Loans | Commercial Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	213,000	213,000
Total	213,000	213,000
Non-Performing Loans | Home Equity
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	14,000	17,000
Total	14,000	17,000
Non-Performing Loans | Commercial & Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Troubled debt restructurings	17,000	29,000
Total	$ 17,000	$ 29,000