Allowance for Loan Losses and Foreclosed Real Estate - Allowance for loan losses allocated by loan class and the activity (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 1,042	$ 855	$ 990	$ 811
Charge-offs				(1)
Recoveries
Provisions	60	45	112	90
Ending Balance	1,102	900	1,102	900
Real estate loans: \| Secured by one-to-four family residences
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	661	539	584	524
Charge-offs
Recoveries
Provisions	29	30	106	45
Ending Balance	690	569	690	569
Real estate loans: \| Secured by multi-family residences
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	45	41	38	39
Charge-offs
Recoveries
Provisions	2	(2)	9
Ending Balance	47	39	47	39
Real estate loans: \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	31	8	31	6
Charge-offs
Recoveries
Provisions	18	10	18	12
Ending Balance	49	18	49	18
Real estate loans: \| Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	107	46	84	35
Charge-offs
Recoveries
Provisions	(1)	1	22	12
Ending Balance	106	47	106	47
Real estate loans: \| Home equity lines of credit
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	114	104	112	101
Charge-offs
Recoveries
Provisions	(5)	1	(3)	4
Ending Balance	109	105	109	105
Other Loans Portfolio Segment \| Commercial & industrial loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	28	11	28	11
Charge-offs
Recoveries
Provisions	10	2	10	2
Ending Balance	38	13	38	13
Other Loans Portfolio Segment \| Other/Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	56	106	113	95
Charge-offs				(1)
Recoveries
Provisions	7	3	(50)	15
Ending Balance	$ 63	$ 109	$ 63	$ 109

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
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