XML 68 R62.htm IDEA: XBRL DOCUMENT
v3.25.3

Loans, Lease Receivables, and Allowance for Credit Losses - Schedule of Amortized Cost Basis of Loans That Had Payment Default (Details) - USD ($) $ in Thousands | 9 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024
Principal Forgiveness |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | $ 0 | $ 0
Payment Delay |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 753
Term Extension |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 397 | 0
Interest Rate Reduction |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial and Industrial | Principal Forgiveness |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial and Industrial | Payment Delay |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 753
Commercial and Industrial | Term Extension |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 397 | 0
Commercial and Industrial | Interest Rate Reduction |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial Real Estate | Principal Forgiveness |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial Real Estate | Payment Delay |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial Real Estate | Term Extension |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | 0 | 0
Commercial Real Estate | Interest Rate Reduction |  |
Financing Receivable, Modified, Subsequent Default [Line Items] |  |
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default | $ 0 | $ 0

X
- Definition Amortized cost excluding accrued interest, of financing receivable with payment default in current period and modified within previous 12 months preceding payment default for debtor experiencing financial difficulty. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 44 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-44 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestModifiedSubsequentDefault
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 44 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-44 + Details
Name: | us-gaap_FinancingReceivableModifiedSubsequentDefaultLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_PrincipalForgivenessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_PaymentDeferralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_InterestRateBelowMarketReductionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fbiz_CommercialandIndustrialLoansandLeasesReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |