Basis of Financial Statement Presentation - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Nov. 12, 2014
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, authorized	20,000,000us-gaap_CommonStockSharesAuthorized	20,000,000us-gaap_CommonStockSharesAuthorized	998,488us-gaap_CommonStockSharesAuthorized
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Net proceeds from stock offering	$ 2,504,000
Share conversion ratio		0.3562bffi_ConversionOfferingExchangeRatio
Contributions to bank	2,000,000bffi_ContributionsToBank
Payments to fund loans for ESOP	273,330
Net proceeds retained by company	314,000
Stock Offering [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Gross proceeds from stock offering	3,900,000
Common stock sold	390,474
Common stock, sale price	$ 10.00
Offering costs	1,400,000
Net proceeds from stock offering	$ 2,500,000
Common Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Share conversion ratio	0.3562	0.3562

Contributions to bank.

No definition available.

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- Definition

Conversion offering exchange ratio.

+ References

No definition available.

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- Definition

Gross Proceeds From Issuance Of Common Stock

+ References

No definition available.

+ Details

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- Definition

Net proceeds from issuances retained by parent.

+ References

No definition available.

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- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

+ Details

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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

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- Definition

The cash outflow to finance the entity's defined contribution plan to acquire shares of the entity. The plan initially holds the shares in a suspense account, which is collateral for the loan. As the plan makes payment on the debt, the shares are released from the suspense account and become available to be allocated to participant accounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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- Definition

The cash outflow for cost incurred directly with the issuance of an equity security.

+ References

+ Details

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- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

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- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

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- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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- Details

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