Capital (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Jul. 25, 2023 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier I capital	$ 113,700,000	$ 107,700,000
CBLR	0.1099	0.1083
Stock authorized for repurchase			$ 4,000,000
Common stock repurchased (in shares) | shares	58,035	46,799
Stock repurchase program, average price (in dollars per share) | $ / shares	$ 36.81	$ 37.05
Stock repurchase program, remaining authorized repurchase amount	$ 1,000
Sound Financial Bancorp
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CBLR	0.0978