Loans (Information on Non-Accrual Loans) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 7,110	$ 6,952	$ 7,110	$ 6,952	$ 8,501
Total non-performing loans	7,110	6,952	7,110	6,952	8,501
Interest income that would have been recorded under original terms, non-accrual loans	143	150	443	370
Interest income that would have been recorded under original terms, 90 days past due and accruing				2
Interest income that would have been recorded under original terms	143	150	443	372
Interest income recorded during the period, 90 days past due and accruing				2
Interest income recorded during the period				2
Net impact on interest income, non-accrual loans	143	150	443	370
Net impact on interest income	143	150	443	370
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,070	1,759	2,070	1,759	1,770
Interest income that would have been recorded under original terms, non-accrual loans	23	15	65	51
Net impact on interest income, non-accrual loans	23	15	65	51
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,311	3,061	2,311	3,061	4,593
Interest income that would have been recorded under original terms, non-accrual loans	33	74	110	139
Net impact on interest income, non-accrual loans	33	74	110	139
Commercial Term [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,506	202	1,506	202	198
Interest income that would have been recorded under original terms, non-accrual loans	27	3	93	9
Net impact on interest income, non-accrual loans	27	3	93	9
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	447	1,217	447	1,217	1,242
Interest income that would have been recorded under original terms, non-accrual loans	46	46	137	134
Net impact on interest income, non-accrual loans	46	46	137	134
Consumer: Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	468	492	468	492	442
Interest income that would have been recorded under original terms, non-accrual loans	5	7	17	23
Net impact on interest income, non-accrual loans	5	7	17	23
Consumer: Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	308	221	308	221	$ 256
Interest income that would have been recorded under original terms, non-accrual loans	9	5	21	14
Net impact on interest income, non-accrual loans	$ 9	$ 5	$ 21	$ 14