Loans Receivable Held for Investment - Risk Category of Loans by Loan Type (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Credit Quality Indicators
Loans receivable	$ 357,618	$ 358,485
Single family
Credit Quality Indicators
Loans receivable	78,359	92,177
Multi-family
Credit Quality Indicators
Loans receivable	248,127	233,309
Commercial real estate
Credit Quality Indicators
Loans receivable	6,397	5,800
Church
Credit Quality Indicators
Loans receivable	21,705	25,096
Construction
Credit Quality Indicators
Loans receivable	2,754	1,872
Commercial - other
Credit Quality Indicators
Loans receivable	271	226
Consumer
Credit Quality Indicators
Loans receivable	5	5
Pass
Credit Quality Indicators
Loans receivable	352,488	352,291
Pass | Single family
Credit Quality Indicators
Loans receivable	78,337	92,132
Pass | Multi-family
Credit Quality Indicators
Loans receivable	247,480	232,642
Pass | Commercial real estate
Credit Quality Indicators
Loans receivable	6,397	5,800
Pass | Church
Credit Quality Indicators
Loans receivable	17,307	19,678
Pass | Construction
Credit Quality Indicators
Loans receivable	2,754	1,872
Pass | Commercial - other
Credit Quality Indicators
Loans receivable	208	162
Pass | Consumer
Credit Quality Indicators
Loans receivable	5	5
Watch
Credit Quality Indicators
Loans receivable	418	672
Watch | Church
Credit Quality Indicators
Loans receivable	418	672
Special Mention
Credit Quality Indicators
Loans receivable		35
Special Mention | Single family
Credit Quality Indicators
Loans receivable		35
Substandard
Credit Quality Indicators
Loans receivable	4,712	5,487
Substandard | Single family
Credit Quality Indicators
Loans receivable	22	10
Substandard | Multi-family
Credit Quality Indicators
Loans receivable	647	667
Substandard | Church
Credit Quality Indicators
Loans receivable	3,980	4,746
Substandard | Commercial - other
Credit Quality Indicators
Loans receivable	$ 63	$ 64