XML 74 R60.htm IDEA: XBRL DOCUMENT
v3.25.3

Summary of Significant Accounting Policies - Allowance for Credit Losses (Details) - USD ($) | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022
--- | --- | --- | --- | ---
Accounting Policies [Abstract] |  |  |  |
Adjustment to opening balance | $ 461,000 |  |  |
Allowance for credit losses | 18,091,000 | $ 17,478,000 | $ 15,817,000 | $ 13,703,000
ACL on unfunded commitments | $ 432,000 | $ 327,000 | $ 332,000 |

X
- Definition Debt Securities, Held-to-Maturity, Allowance For Credit Loss, Excluding Accrued Interest, Adjustment + References No definition available. + Details
Name: | tsbk_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterestAdjustment
Namespace Prefix: | tsbk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | tsbk_ReserveForUnfundedLoanCommitments
Namespace Prefix: | tsbk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -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 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant