Name:	tbnk_DebtSecuritiesHeldToMaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss1
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.

No definition available.

Name:	tbnk_DebtSecuritiesHeldToMaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue1
Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months.

No definition available.

Name:	tbnk_DebtSecuritiesHeldToMaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1
Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.

No definition available.

Name:	tbnk_DebtSecuritiesHeldToMaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue1
Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

No definition available.

Name:	tbnk_DebtSecuritiesHeldToMaturityUnrealizedLossPositionAccumulatedLoss1
Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

No definition available.

Name:	tbnk_DebtSecuritiesHeldToMaturityUnrealizedLossPositionFairValue1
Namespace Prefix:	tbnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

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

Disclosure regarding factors used to determine that the impairment of securities categorized as held-to-maturity where cost exceeds fair value is not an other than temporary impairment (OTTI). This item contains disclosure of the number of investment positions in the held-to-maturity investments determined to be temporarily impaired.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-6