Credit Risk Ratings by Loan Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	$ 929,761	$ 808,754
1-4 Family
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	395,985	388,012
Multifamily
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	232,509	188,550
Nonresidential
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	196,917	151,193
Construction and Land
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	87,572	67,240
Business
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	15,710	12,873
Consumer
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	1,068	886
Pass
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	896,702	780,438
Pass | 1-4 Family
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	383,123	370,629
Pass | Multifamily
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	231,422	188,030
Pass | Nonresidential
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	195,327	148,253
Pass | Construction and Land
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	71,438	59,914
Pass | Business
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	14,324	12,726
Pass | Consumer
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	1,068	886
Special Mention
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	14,394	5,317
Special Mention | 1-4 Family
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	3,728	4,667
Special Mention | Multifamily
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	775
Special Mention | Construction and Land
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	8,505	650
Special Mention | Business
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	1,386
Substandard
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	18,665	22,999
Substandard | 1-4 Family
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	9,134	12,716
Substandard | Multifamily
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	312	520
Substandard | Nonresidential
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	1,590	2,940
Substandard | Construction and Land
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan	$ 7,629	6,676
Substandard | Business
Financing Receivable Recorded Investment [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan		$ 147