Name:	bctf_LoansAndSecuritiesPledgedToSecureFhlbAdvances
Namespace Prefix:	bctf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of loans and securities were pledged to secure public deposits for other purposes required or permitted by law.

No definition available.

Name:	bctf_LoansAndSecuritiesPledgedToSecurePublicDeposits
Namespace Prefix:	bctf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This element represents the securities that exceeded ten percent of stockholders' equity.

No definition available.

Name:	bctf_PercentageOfSecuritiesUsTreasuryAndOtherUsGovernment
Namespace Prefix:	bctf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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

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.

No definition available.