Loans Receivable and Allowance for Credit Losses - Amortized cost basis of loans on nonaccrual status (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with a Related ACL	$ 1,120	$ 1,211
Nonaccrual loans without a Related ACL	115	1,049
Total Nonaccrual Loans	1,235	2,260
One- to four-family residential mortgages
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with a Related ACL	948	1,030
Nonaccrual loans without a Related ACL	115	1,049
Total Nonaccrual Loans	1,063	2,079
Home equity loans and lines of credit
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with a Related ACL	6	11
Total Nonaccrual Loans	6	11
Consumer and other
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with a Related ACL	166	170
Total Nonaccrual Loans	$ 166	$ 170

Amortized cost of financing receivable on nonaccrual status.

No definition available.

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Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of financing receivable on nonaccrual status with allowance for credit loss.

+ References

No definition available.

+ Details

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Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-16

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-16

+ Details

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- Details

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- Details

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- Details

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