Conversion and Stock Issuance (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Aug. 22, 2012	Dec. 31, 2011
Common stock sold (in shares)		1,417,500
Purchase price of sold common stock (in dollars per share)				$ 10
Stock issuance expenses	$ 1,500,000
Proceeds from stock offering, net of offering costs		12,672,000	0
Portion of proceeds used to fund ESOP	1,100,000
Conversion exchange ratio				0.87423
Shares outstanding (in shares)	2,587,544	2,587,544			2,578,144
Sound Financial Bancorp, Inc. [Member]
Dividend made to the Bank (subsidiary) from proceeds of sale	$ 7,500,000
Shares outstanding (in shares)	2,587,544	2,587,544
Stock Sale To Depositors Of Sound Community Bank And Others [Member]
Common stock sold (in shares)	1,417,500
Stock Sale To Sound Community Bank ESOP [Member]
Common stock sold (in shares)	113,400