Loans Receivable Held for Investment - Risk Category of Loans by Loan Type (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Credit Quality Indicators
Loans receivable	$ 367,944	$ 358,485
Single family
Credit Quality Indicators
Loans receivable	89,368	92,177
Multi-family
Credit Quality Indicators
Loans receivable	247,004	233,309
Commercial real estate
Credit Quality Indicators
Loans receivable	6,894	5,800
Church
Credit Quality Indicators
Loans receivable	22,684	25,096
Construction
Credit Quality Indicators
Loans receivable	1,745	1,872
Commercial - other
Credit Quality Indicators
Loans receivable	234	226
Consumer
Credit Quality Indicators
Loans receivable	15	5
Pass
Credit Quality Indicators
Loans receivable	361,627	352,291
Pass | Single family
Credit Quality Indicators
Loans receivable	89,324	92,132
Pass | Multi-family
Credit Quality Indicators
Loans receivable	245,808	232,642
Pass | Commercial real estate
Credit Quality Indicators
Loans receivable	6,894	5,800
Pass | Church
Credit Quality Indicators
Loans receivable	17,670	19,678
Pass | Construction
Credit Quality Indicators
Loans receivable	1,745	1,872
Pass | Commercial - other
Credit Quality Indicators
Loans receivable	171	162
Pass | Consumer
Credit Quality Indicators
Loans receivable	15	5
Watch
Credit Quality Indicators
Loans receivable	667	672
Watch | Church
Credit Quality Indicators
Loans receivable	667	672
Special Mention
Credit Quality Indicators
Loans receivable	795	35
Special Mention | Single family
Credit Quality Indicators
Loans receivable		35
Special Mention | Multi-family
Credit Quality Indicators
Loans receivable	536
Special Mention | Church
Credit Quality Indicators
Loans receivable	259
Substandard
Credit Quality Indicators
Loans receivable	4,855	5,487
Substandard | Single family
Credit Quality Indicators
Loans receivable	44	10
Substandard | Multi-family
Credit Quality Indicators
Loans receivable	660	667
Substandard | Church
Credit Quality Indicators
Loans receivable	4,088	4,746
Substandard | Commercial - other
Credit Quality Indicators
Loans receivable	$ 63	$ 64