Loans Receivable - Balance of Loans Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 883,757	$ 869,730
Net deferred loan fees	206	292
Premium on purchased loans, net	(4,514)	(3,947)
Allowance for loan losses	9,628	9,533	$ 8,760
Total loans receivable, net	878,437	863,852
Residential segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	695,021	725,846
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	147,165	124,986
Commercial business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	41,571	18,898
Allowance for loan losses	208	334	265
Real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	730,200	767,600
Commercial real estate \| Residential segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	255,722	253,235
Allowance for loan losses	2,243	2,289	1,847
Construction and land \| Residential segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	37,187	54,102
Allowance for loan losses	399	585	648
Home equity \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	35,046	37,629
Allowance for loan losses	454	480	787
Auto and other consumer \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	112,119	87,357
Allowance for loan losses	2,261	1,611	712
One- to four-family \| Real estate loans \| Residential segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	306,014	336,178
Allowance for loan losses	3,024	3,297	3,061
Multi-family \| Real estate loans \| Residential segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	96,098	82,331
Allowance for loan losses	$ 888	$ 762	$ 648

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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.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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