Loans Receivable and Allowance for Credit Losses - Narrative (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, net of allowance of $15,606, and $15,227	$ 1,171,916,000	$ 1,167,083,000
Total TDR loans	2,100,000
Recorded Investment	46,084,000	48,521,000
Total loans	1,187,522,000	1,182,310,000
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	1,610,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	44,474,000
Financial Asset, Equal to or Greater than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total TDR loans	0	0
PPP Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, net	629,000		$ 784,000
Property total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired financing receivable, related allowance		13,000
Recorded Investment		48,534,000
Total loans	1,187,522,000
Property total | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	201,000
Property total | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, net of allowance of $15,606, and $15,227	$ 376,000	$ 220,000
Percent of total loans receivable	0.03%	0.02%
Total loans	$ 376,000
Property total | Financial Asset, Equal to or Greater than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	201,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	72,905,000
Consumer | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	201,000
Consumer | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	282,000
Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	201,000	$ 193,000
One-to-four family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	481,593,000
One-to-four family residential | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
FHLB of Des Moines | Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	655,700,000	605,000,000
Federal Reserve Bank | Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 73,900,000	$ 87,700,000