XML 76 R65.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Loans Receivable - Troubled Debt Restructuring (Details) - USD ($) | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Troubled Debt Restructurings |  |
Financing receivable modifications | $ 17,000 | $ 17,000
Non Accrual Loans [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member] |  |
Troubled Debt Restructurings |  |
Financing receivable modifications | $ 17,000 | $ 17,000

X
- Definition Troubled debt restructurings. + References No definition available. + Details
Name: | bfin_TroubledDebtRestructuringsAbstract
Namespace Prefix: | bfin_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings. + References Reference 1: 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=82895541&loc=d3e18845-111554 + Details
Name: | us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | bfin_FinancingReceivableByTypeAxis=bfin_NonAccrualLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bfin_OneToFourFamilyResidentialRealEstateLoansNonOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |