Loans Receivable and Allowance for Credit Losses - Delinquent and Nonaccrual Loans (Details)	12 Months Ended
Dec. 31, 2023
Loans Receivable and Allowance for Credit Losses
Loan delinquency period that may result in loss	90 days
Loan delinquency period after which an appraisal is obtained of the underlying collateral	4 months

Threshold period past due for obtaining appraisal of underlying collateral to financing receivable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	tbnk_ThresholdPeriodPastDueForObtainingAppraisalForCollateralToFinancingReceivable
Namespace Prefix:	tbnk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration