Loans Receivable and Allowance for Loan Losses, Credit Quality Breakdown of Loan Portfolio by Class (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 650,964	$ 610,278	$ 612,458
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	634,233	586,240
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,586	12,412
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,145	11,626
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	289,169	257,659	268,896
Residential Mortgage [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	281,954	248,819
Residential Mortgage [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,397	4,316
Residential Mortgage [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,818	4,524
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	37,485	46,468	42,359
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	37,299	46,011
Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	50	204
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	136	253
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	223,167	195,710	198,915
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	216,373	184,820
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,668	7,420
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,126	3,470
ADC [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	84,164	90,102	81,340
ADC [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	82,958	89,324
ADC [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
ADC [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,206	778
Home Equity/2nds[Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,861	19,129	19,739
Home Equity/2nds[Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,531	16,056
Home Equity/2nds[Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	471	472
Home Equity/2nds[Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	859	2,601
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,118	1,210	$ 1,209
Consumer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,118	1,210
Consumer [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Consumer [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0