Loans Receivable And Allowance For Loan Losses: Schedule of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	$ 14,698	$ 13,433	$ 13,703	$ 13,469
Provision for (Recapture of) Loan Losses	610	0	1,610	0
Charge- offs	(1)	(8)	(7)	(59)
Recoveries	0	8	1	23
Allowance for loan losses, Ending Allowance	15,307	13,433	15,307	13,433
Mortgage loans, one-to-four family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	2,052	1,247	1,658	1,154
Provision for (Recapture of) Loan Losses	126	109	520	202
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	2,178	1,356	2,178	1,356
Mortgage loans, multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	938	735	855	765
Provision for (Recapture of) Loan Losses	74	153	157	123
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	1,012	888	1,012	888
Mortgage loans, commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	6,904	6,931	6,682	6,813
Provision for (Recapture of) Loan Losses	125	(168)	347	(50)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	7,029	6,763	7,029	6,763
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	726	686	675	644
Provision for (Recapture of) Loan Losses	73	47	124	89
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	799	733	799	733
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	121	126	130	188
Provision for (Recapture of) Loan Losses	(11)	(33)	(20)	(95)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	110	93	110	93
Mortgage loans, construction – commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	267	463	343	784
Provision for (Recapture of) Loan Losses	24	(109)	(52)	(430)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	291	354	291	354
Mortgage loans, construction - Multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	662	436	447	436
Provision for (Recapture of) Loan Losses	30	(108)	245	(108)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	692	328	692	328
Mortgage loans, construction - Land development
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	245	126	233	124
Provision for (Recapture of) Loan Losses	(12)	113	0	115
Charge- offs	0		0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	233	239	233	239
Mortgage loans, land
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	363	377	397	470
Provision for (Recapture of) Loan Losses	26	(17)	(8)	(110)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	389	360	389	360
Consumer loans, home equity and second mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	507	469	440	528
Provision for (Recapture of) Loan Losses	35	(35)	102	(94)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	542	434	542	434
Consumer loans, other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	47	44	42	50
Provision for (Recapture of) Loan Losses	5	15	11	10
Charge- offs	(1)	(8)	(2)	(10)
Recoveries	0	0	0	1
Allowance for loan losses, Ending Allowance	51	51	51	51
Commercial business loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	1,866	1,793	1,801	1,513
Provision for (Recapture of) Loan Losses	115	33	184	348
Charge- offs	0	0	(5)	(49)
Recoveries	0	8	1	22
Allowance for loan losses, Ending Allowance	1,981	$ 1,834	1,981	$ 1,834
SBA PPP Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance			0
Allowance for loan losses, Ending Allowance	$ 0		$ 0

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (3)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (c)
-Publisher SEC

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase in allowance for credit loss on financing receivable from recovery.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-79

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(4)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of writeoff of financing receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-79

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Name:	us-gaap_ProvisionForLoanLeaseAndOtherLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_MortgageLoansOneToFourFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_MortgageLoansMultiFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConstructionCustomAndOwnerbuilderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConstructionSpeculativeOneToFourFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConstructionCommercialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConstructionMultiFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConstructionLandDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_MortgageLoansLandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_ConsumerLoansHomeEquityAndSecondMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=tsbk_SBAPPPLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: