Loans Receivable Held for Investment - Aging of Recorded Investment in Past Due Loans by Loan Type (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Past due receivable
Total Past Due	$ 35	$ 391
Current	358,450	338,529
Gross loans receivable after deferred loan costs and premiums	358,485	338,920
30-59 Days Past Due
Past due receivable
Total Past Due	35	341
60-89 Days Past Due
Past due receivable
Total Past Due		50
Single family
Past due receivable
Total Past Due	35	50
Current	92,142	111,474
Gross loans receivable after deferred loan costs and premiums	92,177	111,524
Single family | 30-59 Days Past Due
Past due receivable
Total Past Due	35
Single family | 60-89 Days Past Due
Past due receivable
Total Past Due		50
Multi-family
Past due receivable
Current	233,309	188,918
Gross loans receivable after deferred loan costs and premiums	233,309	188,918
Commercial real estate
Past due receivable
Current	5,800	6,096
Gross loans receivable after deferred loan costs and premiums	5,800	6,096
Church
Past due receivable
Total Past Due		341
Current	25,096	30,171
Gross loans receivable after deferred loan costs and premiums	25,096	30,512
Church | 30-59 Days Past Due
Past due receivable
Total Past Due		341
Construction
Past due receivable
Current	1,872	1,671
Gross loans receivable after deferred loan costs and premiums	1,872	1,671
Commercial - other
Past due receivable
Current	226	192
Gross loans receivable after deferred loan costs and premiums	226	192
Consumer
Past due receivable
Current	5	7
Gross loans receivable after deferred loan costs and premiums	$ 5	$ 7