Loans Receivable - Nonaccrual Loans by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	$ 1,796	$ 1,723
Nonperforming | Residential segment | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	109	133
Nonperforming | Residential segment | Construction and land
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	29	44
Nonperforming | Consumer | Home equity
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	112	369
Nonperforming | Consumer | Auto and other consumer
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	848	245
Nonperforming | Consumer | Commercial business loans
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	0	173
Nonperforming | One- to four-family | Residential segment | Real estate loans
Financing Receivable, Past Due [Line Items]
Total nonaccrual loans	$ 698	$ 759