XML 79 R65.htm IDEA: XBRL DOCUMENT v3.24.0.1

Securities (Narrative Disclosures) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) securities	Dec. 31, 2022 USD ($) securities	Dec. 31, 2021 USD ($) securities
Investments, Debt and Equity Securities [Abstract]
Number of available-for-sale securities sold | securities	16	0	7
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Recognized in Earnings	$ 0	$ 0
Held-to-maturity securities in unrealized loss positions | securities	29
Held-to-maturity securities in an unrealized loss position, twelve months or greater | securities	24
Other than temporary impairment on held-to-maturity securities	$ 0	0	$ 0
Investment in limited partnerships	15,027	13,599
Various Obligations
Investments, Debt and Equity Securities [Abstract]
Debt Securities	45,400	35,900
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt Securities	$ 45,400	$ 35,900

X

- Definition

Held-to-Maturity Securities, Securities in Unrealized Loss Positions, Qualitative Disclosures, Number of Positions 12 months or greater

+ References

No definition available.

+ Details

Name:	fbiz_HeldtoMaturitySecuritiesSecuritiesinUnrealizedLossPositionsQualitativeDisclosuresNumberofPositions12monthsorgreater
Namespace Prefix:	fbiz_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Investment in Limited Partnerships

+ References

No definition available.

+ Details

Name:	fbiz_InvestmentinLimitedPartnerships
Namespace Prefix:	fbiz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Number of available-for-sale securities sold

+ References

No definition available.

+ Details

Name:	fbiz_Numberofavailableforsalesecuritiessold
Namespace Prefix:	fbiz_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-1

+ Details

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

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/disclosureRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481444/860-30-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

+ Details

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

X

- Definition

Disclosure regarding factors used to determine that the impairment of securities categorized as held-to-maturity where cost exceeds fair value is not an other than temporary impairment (OTTI). This item contains disclosure of the number of investment positions in the held-to-maturity investments determined to be temporarily impaired.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-6

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-8A

+ Details

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

X

- Definition

Amount, before tax, of other-than-temporary impairment (OTTI) on investment in debt security measured at amortized cost (held-to-maturity), recognized in earnings and other comprehensive income (OCI).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-8A

+ Details

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

X

- Details

Name:	us-gaap_PledgingPurposeAxis=fbiz_VariousObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: