Loans Receivable Held for Investment - Aging of Recorded Investment in Past Due Loans by Loan Type (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Past due receivable
Total Past Due	$ 250	$ 35
Current	357,368	358,450
Gross loans receivable after deferred loan costs and premiums	357,618	358,485
30-59 Days Past Due
Past due receivable
Total Past Due		35
60-89 Days Past Due
Past due receivable
Total Past Due	250
Single family
Past due receivable
Total Past Due		35
Current	78,359	92,142
Gross loans receivable after deferred loan costs and premiums	78,359	92,177
Single family | 30-59 Days Past Due
Past due receivable
Total Past Due		35
Multi-family
Past due receivable
Current	248,127	233,309
Gross loans receivable after deferred loan costs and premiums	248,127	233,309
Commercial real estate
Past due receivable
Current	6,397	5,800
Gross loans receivable after deferred loan costs and premiums	6,397	5,800
Church
Past due receivable
Total Past Due	250
Current	21,455	25,096
Gross loans receivable after deferred loan costs and premiums	21,705	25,096
Church | 60-89 Days Past Due
Past due receivable
Total Past Due	250
Construction
Past due receivable
Current	2,754	1,872
Gross loans receivable after deferred loan costs and premiums	2,754	1,872
Commercial - other
Past due receivable
Current	271	226
Gross loans receivable after deferred loan costs and premiums	271	226
Consumer
Past due receivable
Current	5	5
Gross loans receivable after deferred loan costs and premiums	$ 5	$ 5