Document and Entity Information (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Nov. 30, 2013	Mar. 31, 2013
Document and Entity Information
Entity Registrant Name	TIMBERLAND BANCORP INC,
Entity Central Index Key	0001046050
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Document Type	10-K
Document Period End Date	Sep. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		7,047,636
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 57.8