Loans Receivable and Allowance for Loan Losses, Credit Quality Breakdown of Loan Portfolio by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	$ 668,151	$ 610,278
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	651,261	586,240
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	6,687	12,412
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	10,203	11,626
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	284,646	257,659
Residential Mortgage [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	277,867	248,819
Residential Mortgage [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	1,563	4,316
Residential Mortgage [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	5,216	4,524
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	37,356	46,468
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	37,312	46,011
Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	44	204
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	0	253
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	236,302	195,710
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	228,746	184,820
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	4,615	7,420
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	2,941	3,470
ADC [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	93,060	90,102
ADC [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	91,868	89,324
ADC [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	0	0
ADC [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	1,192	778
Home Equity/2nds[Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	15,703	19,129
Home Equity/2nds[Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	14,384	16,056
Home Equity/2nds[Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	465	472
Home Equity/2nds[Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	854	2,601
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	1,084	1,210
Consumer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	1,084	1,210
Consumer [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	0	0
Consumer [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans (change)	$ 0	$ 0