Nonaccrual Loans (Details) - Nonperforming - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	$ 11,776	$ 6,776
One-to-four family
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	3,671	3,582
Multifamily
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	373	375
Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	4,139	0
Business
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	3,571	2,797
Consumer
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual	$ 22	$ 22