Loans Receivable and Related Allowance for Loan Losses - Activity in Allowance for Loan Losses by Portfolio (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	$ 5,205	$ 5,224
Charge-offs	(296)	(567)
Recoveries	172	167
Provision	464	381
Balance at the end of the year	5,545	5,205
Ending ALL balance attributable to loans:
Individually evaluated for impairment	120	110
Acquired loans	0
Collectively evaluated for impairment	5,425	5,095
Total loans:
Individually evaluated for impairment	1,833	2,007
Acquired loans	58,936
Collectively evaluated for impairment	460,211	433,089
Total loans, gross	520,980	435,096
Residential Mortgages
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	1,429	955
Charge-offs	(101)	(79)
Recoveries	0	0
Provision	518	553
Balance at the end of the year	1,846	1,429
Ending ALL balance attributable to loans:
Individually evaluated for impairment	19	29
Acquired loans	0
Collectively evaluated for impairment	1,827	1,400
Total loans:
Individually evaluated for impairment	135	169
Acquired loans	25,024
Collectively evaluated for impairment	173,008	139,136
Total loans, gross	198,167	139,305
Home Equity & Lines of Credit
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	586	543
Charge-offs	(118)	(221)
Recoveries	3	30
Provision	162	234
Balance at the end of the year	633	586
Ending ALL balance attributable to loans:
Individually evaluated for impairment	0	0
Acquired loans	0
Collectively evaluated for impairment	633	586
Total loans:
Individually evaluated for impairment	0	0
Acquired loans	5,225
Collectively evaluated for impairment	86,134	87,410
Total loans, gross	91,359	87,410
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	2,185	2,338
Charge-offs	(18)	(35)
Recoveries	158	88
Provision	(11)	(206)
Balance at the end of the year	2,314	2,185
Ending ALL balance attributable to loans:
Individually evaluated for impairment	95	5
Acquired loans	0
Collectively evaluated for impairment	2,219	2,180
Total loans:
Individually evaluated for impairment	1,014	839
Acquired loans	27,492
Collectively evaluated for impairment	138,488	128,852
Total loans, gross	166,994	129,691
Commercial Business
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	960	1,336
Charge-offs	(11)	(182)
Recoveries	0	31
Provision	(249)	(225)
Balance at the end of the year	700	960
Ending ALL balance attributable to loans:
Individually evaluated for impairment	6	76
Acquired loans	0
Collectively evaluated for impairment	694	884
Total loans:
Individually evaluated for impairment	684	999
Acquired loans	1,182
Collectively evaluated for impairment	55,922	70,949
Total loans, gross	57,788	71,948
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at the beginning of the year	45	52
Charge-offs	(48)	(50)
Recoveries	11	18
Provision	44	25
Balance at the end of the year	52	45
Ending ALL balance attributable to loans:
Individually evaluated for impairment	0	0
Acquired loans	0
Collectively evaluated for impairment	52	45
Total loans:
Individually evaluated for impairment	0	0
Acquired loans	13
Collectively evaluated for impairment	6,659	6,742
Total loans, gross	$ 6,672	$ 6,742