XML 65 R59.htm IDEA: XBRL DOCUMENT v3.25.3

Loans, Lease Receivables, and Allowance for Credit Losses - Schedule of Amortized Cost Basis of Loan (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,318	$ 8,225
Percentage of total loans	0.19%	0.27%
Principal Forgiveness
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 0	$ 0
Payment Delay
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	7,748
Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	477
Interest Rate Reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	302	0
Combination Payment Delay and Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	6,016	0
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,318	$ 2,324
Percentage of total loans	0.50%	0.20%
Commercial and Industrial | Principal Forgiveness
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 0	$ 0
Commercial and Industrial | Payment Delay
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	1,847
Commercial and Industrial | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	477
Commercial and Industrial | Interest Rate Reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	302	0
Commercial and Industrial | Combination Payment Delay and Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	6,016	0
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 0	$ 5,901
Percentage of total loans	0.00%	0.32%
Commercial Real Estate | Principal Forgiveness
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 0	$ 0
Commercial Real Estate | Payment Delay
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	5,901
Commercial Real Estate | Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	0
Commercial Real Estate | Interest Rate Reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	0	0
Commercial Real Estate | Combination Payment Delay and Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 0	$ 0

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/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

+ Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period 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 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Percentage, excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty to total financing receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

+ Details

Name:	us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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_LoanRestructuringModificationAxis=fbiz_CombinationPaymentDelayAndTermExtensionMember
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: