Loans (Information on Non-Accrual Loans) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 6,471	$ 7,110	$ 6,471	$ 7,110	$ 7,499
Loans 90 day past due and accruing					54
Total non-performing loans	6,471	7,110	6,471	7,110	7,553
Interest income that would have been recorded under original terms, non-accrual loans	110	143	340	443
Interest income that would have been recorded under original terms	110	143	340	443
Net impact on interest income, non-accrual loans	110	143	340	443
Net impact on interest income	110	143	340	443
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,005	2,070	1,005	2,070	1,915
Interest income that would have been recorded under original terms, non-accrual loans	9	23	52	65
Net impact on interest income, non-accrual loans	9	23	52	65
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,561	2,311	1,561	2,311	2,259
Interest income that would have been recorded under original terms, non-accrual loans	30	33	88	110
Net impact on interest income, non-accrual loans	30	33	88	110
Commercial Term [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,624	1,506	2,624	1,506	2,100
Interest income that would have been recorded under original terms, non-accrual loans	50	27	140	93
Net impact on interest income, non-accrual loans	50	27	140	93
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	479	447	479	447	514
Interest income that would have been recorded under original terms, non-accrual loans	9	46	29	137
Net impact on interest income, non-accrual loans	9	46	29	137
Consumer: Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	631	468	631	468	466
Interest income that would have been recorded under original terms, non-accrual loans	9	5	17	17
Net impact on interest income, non-accrual loans	9	5	17	17
Consumer: Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	171	308	171	308	245
Loans 90 day past due and accruing					$ 54
Interest income that would have been recorded under original terms, non-accrual loans	3	9	14	21
Net impact on interest income, non-accrual loans	$ 3	$ 9	$ 14	$ 21