v3.21.2

Loans and Allowance for Loan Losses - Additional information (Details)	12 Months Ended
	Jun. 30, 2021 USD ($) loan	Jun. 30, 2020 USD ($) loan
Loans and Allowance for Loan Losses
Aggregate Amount of Purchased Participants	$ 5,500,000	$ 5,600,000
Aggregate Amount of Purchased Participants, Portion	$ 29,300,000	$ 9,000,000
Number of loans past due 90 days or over that were not on nonaccrual \| loan	0	0
Loans outstanding to certain directors and executive officers of the Bank	$ 1,063,485	$ 1,080,531
Number of new related party loans \| loan	1	1
Related party loan addition	$ 384,000	$ 90,400
Number of related party loan receivables paid off \| loan	1
Related parties loans receivable paid off	$ 357,261
Repayments of related party loans	$ 43,784	$ 49,768
TDR's granted during the period \| loan	2	1
TDR's outstanding	$ 105,000	$ 195,924
TDR's defaulted during the period \| loan	0
TDR granted and subsequently transferred out of TDR status during the period \| loan	1

The aggregate amount of purchased participants.

+ References

No definition available.

+ Details

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Namespace Prefix:	tbba_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate amount of our portion of purchased participants.

+ References

No definition available.

+ Details

Name:	tbba_AggregateAmountOfPurchasedParticipantsPortion
Namespace Prefix:	tbba_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings and subsequently transferred out of TDR status during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	tbba_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of loans past due 90 days or over that were not on nonaccrual.

+ References

No definition available.

+ Details

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Namespace Prefix:	tbba_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of related party loan entered into during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	tbba_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of related party loan receivables paid off.

+ References

No definition available.

+ Details

Name:	tbba_NumberOfRelatedPartiesLoansReceivablePaidOff
Namespace Prefix:	tbba_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(e))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the amount of new advances made to related parties in the form of loan and lease receivables.

+ References

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

- Definition

Amount of cash inflow from related parties which reduce the amount of loans and leases receivable due from related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(e)(1)(i))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

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

- References

No definition available.

+ Details

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

- Definition

The cash inflow from a loan, supported by a promissory note, granted to related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

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

TEB Bancorp, Inc. 10-K