Loans Receivable Held for Investment - Aging of Recorded Investment in Past Due Loans by Loan Type (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Past due receivable
Total Past Due	$ 576	$ 35
Current	367,368	358,450
Gross loans receivable after deferred loan costs and premiums	367,944	358,485
30-59 Days Past Due
Past due receivable
Total Past Due	259	35
60-89 Days Past Due
Past due receivable
Total Past Due	283
Greater than 90 Days Past Due
Past due receivable
Total Past Due	34
Single family
Past due receivable
Total Past Due	34	35
Current	89,334	92,142
Gross loans receivable after deferred loan costs and premiums	89,368	92,177
Single family | 30-59 Days Past Due
Past due receivable
Total Past Due		35
Single family | Greater than 90 Days Past Due
Past due receivable
Total Past Due	34
Multi-family
Past due receivable
Current	247,004	233,309
Gross loans receivable after deferred loan costs and premiums	247,004	233,309
Commercial real estate
Past due receivable
Current	6,894	5,800
Gross loans receivable after deferred loan costs and premiums	6,894	5,800
Church
Past due receivable
Total Past Due	542
Current	22,142	25,096
Gross loans receivable after deferred loan costs and premiums	22,684	25,096
Church | 30-59 Days Past Due
Past due receivable
Total Past Due	259
Church | 60-89 Days Past Due
Past due receivable
Total Past Due	283
Construction
Past due receivable
Current	1,745	1,872
Gross loans receivable after deferred loan costs and premiums	1,745	1,872
Commercial - other
Past due receivable
Current	234	226
Gross loans receivable after deferred loan costs and premiums	234	226
Consumer
Past due receivable
Current	15	5
Gross loans receivable after deferred loan costs and premiums	$ 15	$ 5