Loans - Schedule of Investment in Nonaccrual Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	$ 3,366	$ 7,491
Total Nonaccrual Loans with no ACL	3,365	7,489
Real estate loans: \| One-to-four family:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	1,423	537
Total Nonaccrual Loans with no ACL	1,423	537
Real estate loans: \| Home equity:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	359	298
Total Nonaccrual Loans with no ACL	359	298
Real estate loans: \| Commercial and multifamily:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	1,065	3,734
Total Nonaccrual Loans with no ACL	1,065	3,734
Real estate loans: \| Construction and land:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	21	24
Total Nonaccrual Loans with no ACL	21	24
Consumer loans: \| Manufactured homes:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	489	521
Total Nonaccrual Loans with no ACL	489	521
Consumer loans: \| Floating homes:
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	0	2,363
Total Nonaccrual Loans with no ACL	0	2,363
Consumer loans: \| Other consumer
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	9	3
Total Nonaccrual Loans with no ACL	8	1
Commercial business loans
Financing Receivable, Past Due [Line Items]
Total Nonaccrual Loans	0	11
Total Nonaccrual Loans with no ACL	$ 0	$ 11

Sound Financial Bancorp, Inc. 10-Q