v3.26.1
Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details) - EBP 002
12 Months Ended
Sep. 30, 2025
USD ($)
shares
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity tax identification number 20-5645878
Plan number 002
Current Value $ 39,778,676
Common Stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 13,048,156
Mutual Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 26,730,520
Investment, Identifier [Axis]: Dimensional Fund Advisors | Inflation Protected Securities I  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 278,420
Investment, Identifier [Axis]: Dimensional Fund Advisors | International Small Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 134,080
Investment, Identifier [Axis]: Dimensional Fund Advisors | International Value I  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 92,442
Investment, Identifier [Axis]: Dimensional Fund Advisors | Large Company Institutional  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 919,111
Investment, Identifier [Axis]: Dimensional Fund Advisors | Real Estate Securities I  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 305,718
Investment, Identifier [Axis]: Dimensional Fund Advisors | U.S. Large Cap Value  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 705,182
Investment, Identifier [Axis]: Dimensional Fund Advisors | U.S. Target Value  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value $ 805,060
Investment, Identifier [Axis]: Timberland Bancorp, Inc. | Common Stock – 123,975 Shares  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Shares | shares 123,975
Current Value $ 4,125,888
Investment, Identifier [Axis]: Timberland Bancorp, Inc. | Common Stock – 268,097 Shares  
EBP, Schedule of Asset Held for Investment [Line Items]  
Cost $ 2,009,387
Number of Shares | shares 268,097
Current Value $ 8,922,268
Investment, Identifier [Axis]: Vanguard | Balanced Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 615,069
Investment, Identifier [Axis]: Vanguard | Emerging Markets Stock Index  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 77,654
Investment, Identifier [Axis]: Vanguard | Federal Money Market Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 2,189,848
Investment, Identifier [Axis]: Vanguard | Growth Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 767,184
Investment, Identifier [Axis]: Vanguard | LifeStategy Growth  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 2,781,725
Investment, Identifier [Axis]: Vanguard | LifeStrategy Conservative Growth  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 1,043,203
Investment, Identifier [Axis]: Vanguard | LifeStrategy Income  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 252,551
Investment, Identifier [Axis]: Vanguard | LifeStrategy Moderate Growth  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 3,055,635
Investment, Identifier [Axis]: Vanguard | Mid Cap Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 435,186
Investment, Identifier [Axis]: Vanguard | Short-Term Investment Grade  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 81,650
Investment, Identifier [Axis]: Vanguard | Small Cap Growth Index Institutional  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 1,130,365
Investment, Identifier [Axis]: Vanguard | Target Retirement 2020  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 1,347
Investment, Identifier [Axis]: Vanguard | Target Retirement 2025  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 438,586
Investment, Identifier [Axis]: Vanguard | Target Retirement 2030  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 555,514
Investment, Identifier [Axis]: Vanguard | Target Retirement 2035  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 1,087,740
Investment, Identifier [Axis]: Vanguard | Target Retirement 2040  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 237,459
Investment, Identifier [Axis]: Vanguard | Target Retirement 2045  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 422,360
Investment, Identifier [Axis]: Vanguard | Target Retirement 2050  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 390,547
Investment, Identifier [Axis]: Vanguard | Target Retirement 2055  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 526,601
Investment, Identifier [Axis]: Vanguard | Target Retirement 2060  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 426,544
Investment, Identifier [Axis]: Vanguard | Target Retirement 2065  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 476,122
Investment, Identifier [Axis]: Vanguard | Target Retirement Income  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 118,394
Investment, Identifier [Axis]: Vanguard | Total Bond Market Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 563,040
Investment, Identifier [Axis]: Vanguard | Total International Stock Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 931,277
Investment, Identifier [Axis]: Vanguard | Total Stock Market Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value 2,504,308
Investment, Identifier [Axis]: Vanguard | Total World Stock Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current Value $ 2,380,598