Name:	bctf_FinancingReceivableRecordedInvestmentNonperformingAssetsToGrossLoansAndOtherRealEstatePercentage
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Data Type:	num:percentItemType
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Percentage amount of recorded investment in financing receivables that are on nonperforming assets to total assets reporting period.

No definition available.

Name:	bctf_FinancingReceivableRecordedInvestmentNonperformingAssetsToTotalAssetsPercentage
Namespace Prefix:	bctf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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Period Type:	instant

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

Name:	us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Period Type:	instant

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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=bctf_OnetofourFamilyResidentialRealEstatePortfolioSegmentMember
Namespace Prefix:
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=bctf_CommercialAndIndustrialPortfolioSegmentMember
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