Loans Receivable and Related Allowance for Loan Losses - Nonaccrual Loans by Aging Category (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 2,938	$ 3,278
Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,033	1,100
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	433	77
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	557
90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,472	1,544
Residential first mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	742	1,126
Residential first mortgages | Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	71	72
Residential first mortgages | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	394	77
Residential first mortgages | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Residential first mortgages | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	277	977
Home equity loans and lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	528	340
Home equity loans and lines of credit | Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Home equity loans and lines of credit | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Home equity loans and lines of credit | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Home equity loans and lines of credit | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	528	340
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,027	1,073
Commercial real estate | Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	384	397
Commercial real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Commercial real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	557
Commercial real estate | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	643	119
Commercial business
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	641	726
Commercial business | Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	578	631
Commercial business | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	39	0
Commercial business | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Commercial business | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	24	95
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	13
Consumer | Not Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	0	0
Consumer | 90 Days and Greater Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 0	$ 13