$FBIZ
FIRST BUSINESS FINANCIAL SERVICES, INC. Stock $fbiz

$fbiz Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-K Financial Statement

#000152195122000016 Filed on February 23, 2022

Income Statement

Concept	2021 Q4	2021 Q3	2021
Revenue	$23.58M	$24.01M	$96.00M
YoY Change	-8.52%	7.8%	1.93%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$850.0K	$850.0K	$585.0K
YoY Change	-11.46%	-2.3%	-28.83%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$2.651M	$2.791M	$11.33M
YoY Change	-18.63%	-23.64%	-33.76%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$11.47M	$12.02M	$47.03M
YoY Change	56.31%	121.06%	156.92%
Income Tax	$2.879M	$2.819M	$11.28M
% Of Pretax Income	25.1%	23.46%	23.97%
Net Earnings	$8.591M	$9.198M	$35.76M
YoY Change	41.21%	114.26%	110.6%
Net Earnings / Revenue	36.44%	38.3%	37.25%
Basic Earnings Per Share	$1.01	$1.07	$4.17
Diluted Earnings Per Share	$1.01	$1.07	$4.17
COMMON SHARES
Basic Shares Outstanding	8.390M shares	8.340M shares	8.315M shares
Diluted Shares Outstanding		8.340M shares	8.315M shares

Balance Sheet

Concept	2021 Q4	2021 Q3	2021
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$57.11M	$110.6M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$1.694M	$1.700M	$6.600M
YoY Change	-15.22%	-20.19%	-15.38%
Goodwill	$10.70M
YoY Change	0.0%
Intangibles
YoY Change
Long-Term Investments	$15.50M	$18.50M	$15.50M
YoY Change	8.39%	37.04%	8.39%
Other Assets	$6.200M	$4.900M	$6.200M
YoY Change	-13.89%	-35.53%	-13.89%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$2.653B	$2.584B	$2.653B
YoY Change	3.31%	-0.67%	3.31%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$15.30M	$13.00M	$15.30M
YoY Change	-1.92%	-83.63%	-1.92%
Accrued Expenses	$5.400M	$5.800M	$5.400M
YoY Change	-15.63%	-13.43%	-15.63%
Deferred Revenue
YoY Change
Short-Term Debt	$500.0K	$0.00	$500.0K
YoY Change		-100.0%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$20.70M	$18.80M	$20.70M
YoY Change	-5.91%	-78.16%	-5.91%
LONG-TERM LIABILITIES
Long-Term Debt	$44.20M	$46.40M	$44.20M
YoY Change	27.38%	34.49%	27.38%
Other Long-Term Liabilities	$28.30M	$31.90M	$28.30M
YoY Change	-48.45%		-48.45%
Total Long-Term Liabilities	$72.50M	$78.30M	$72.50M
YoY Change	-19.08%	126.96%	-19.08%
TOTAL LIABILITIES
Total Short-Term Liabilities	$20.70M	$18.80M	$20.70M
Total Long-Term Liabilities	$72.50M	$78.30M	$72.50M
Total Liabilities	$2.420B	$2.359B	$2.421B
YoY Change	2.49%	-1.75%	2.49%
SHAREHOLDERS EQUITY
Retained Earnings	$170.0M	$163.0M
YoY Change	21.07%	20.03%
Common Stock	$85.89M	$85.05M
YoY Change	3.21%	2.83%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$22.03M	$21.27M
YoY Change	33.09%	28.77%
Treasury Stock Shares	868.8K shares	842.6K shares
Shareholders Equity	$232.4M	$225.3M	$232.4M
YoY Change
Total Liabilities & Shareholders Equity	$2.653B	$2.584B	$2.653B
YoY Change	3.31%	-0.67%	3.31%

Cashflow Statement

Concept	2021 Q4	2021 Q3	2021
OPERATING ACTIVITIES
Net Income	$8.591M	$9.198M	$35.76M
YoY Change	41.21%	114.26%	110.6%
Depreciation, Depletion And Amortization	$850.0K	$850.0K	$585.0K
YoY Change	-11.46%	-2.3%	-28.83%
Cash From Operating Activities	$11.23M	$9.790M	$35.99M
YoY Change	-47.08%	138.2%	35.13%
INVESTING ACTIVITIES
Capital Expenditures	-$170.0K	-$80.00K	-$390.0K
YoY Change	183.33%	33.33%	50.0%
Acquisitions
YoY Change
Other Investing Activities	-$125.3M	-$1.350M	-$110.6M
YoY Change	-902.43%	-98.9%	-75.65%
Cash From Investing Activities	-$125.5M	-$1.440M	-$111.0M
YoY Change	-907.14%	-98.83%	-75.58%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$5.478M
YoY Change			227.63%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	60.76M	-287.7M	$75.22M
YoY Change	-292.34%	-324.89%	-81.99%
NET CHANGE
Cash From Operating Activities	11.23M	9.790M	$35.99M
Cash From Investing Activities	-125.5M	-1.440M	-$111.0M
Cash From Financing Activities	60.76M	-287.7M	$75.22M
Net Change In Cash	-53.52M	-279.4M	$201.0K
YoY Change	-1133.2%	-3090.9%	-101.97%
FREE CASH FLOW
Cash From Operating Activities	$11.23M	$9.790M	$35.99M
Capital Expenditures	-$170.0K	-$80.00K	-$390.0K
Free Cash Flow	$11.40M	$9.870M	$36.38M
YoY Change	-46.43%	136.69%	35.27%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0001521951
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Amendment Flag AmendmentFlag	false
CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	001-34095
CY2021	dei	Entity Registrant Name EntityRegistrantName	FIRST BUSINESS FINANCIAL SERVICES, INC.
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	WI
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	39-1576570
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	401 Charmany Drive
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Madison
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	WI
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	53719
CY2021	dei	City Area Code CityAreaCode	608
CY2021	dei	Local Phone Number LocalPhoneNumber	238-8008
CY2021	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value
CY2021	dei	Trading Symbol TradingSymbol	FBIZ
CY2021	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2021	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2021	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2021	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2021	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
CY2021	dei	Entity Small Business EntitySmallBusiness	true
CY2021	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2021	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
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CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11275000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1327000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	35755000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	16978000	USD
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.17
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.97
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.17
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.72
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.66
CY2021	us-gaap	Net Income Loss NetIncomeLoss	35755000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	16978000	USD
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-4312000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	3526000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	29000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-4000	USD
CY2021	fbiz	Other Comprehensive Income Loss Amortizationof Net Unrealized Losses Transferredto Heldto Maturityfrom Availablefor Salebeforetax OtherComprehensiveIncomeLossAmortizationofNetUnrealizedLossesTransferredtoHeldtoMaturityfromAvailableforSalebeforetax	26000	USD
CY2020	fbiz	Other Comprehensive Income Loss Amortizationof Net Unrealized Losses Transferredto Heldto Maturityfrom Availablefor Salebeforetax OtherComprehensiveIncomeLossAmortizationofNetUnrealizedLossesTransferredtoHeldtoMaturityfromAvailableforSalebeforetax	39000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	3610000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-3011000	USD
CY2021	us-gaap	Other Comprehensive Income Availableforsale Securities Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesTaxPortionAttributableToParent	-181000	USD
CY2020	us-gaap	Other Comprehensive Income Availableforsale Securities Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesTaxPortionAttributableToParent	143000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-524000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	415000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	35231000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	17393000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	194156000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	16978000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	415000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1871000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Employee Stock Purchase Program Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition	66000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	5652000	USD
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1672000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	206162000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	35755000	USD
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-524000	USD
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2513000	USD
CY2021	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Employee Stock Purchase Program Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition	160000	USD
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6166000	USD
CY2021	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	5478000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	232422000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	35755000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	16978000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1223000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2007000	USD
CY2021	fbiz	Impairmentof Tax Credit Investments ImpairmentofTaxCreditInvestments	0	USD
CY2020	fbiz	Impairmentof Tax Credit Investments ImpairmentofTaxCreditInvestments	2395000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-5803000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	16808000	USD
CY2021	fbiz	Sba Recourse Provision SBARecourseProvision	-76000	USD
CY2020	fbiz	Sba Recourse Provision SBARecourseProvision	-278000	USD
CY2021	fbiz	Derivative Credit Valuation Adjustment DerivativeCreditValuationAdjustment	-270000	USD
CY2020	fbiz	Derivative Credit Valuation Adjustment DerivativeCreditValuationAdjustment	461000	USD
CY2021	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	3554000	USD
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	3465000	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	2513000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	1871000	USD
CY2021	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-78000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	0	USD
CY2021	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	29000	USD
CY2020	us-gaap	Marketable Securities Gain Loss MarketableSecuritiesGainLoss	-4000	USD
CY2021	fbiz	Gainon Saleof Historic Development Entity Tax Credit GainonSaleofHistoricDevelopmentEntityTaxCredit	0	USD
CY2020	fbiz	Gainon Saleof Historic Development Entity Tax Credit GainonSaleofHistoricDevelopmentEntityTaxCredit	275000	USD
CY2021	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1413000	USD
CY2020	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1402000	USD
CY2021	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	99266000	USD
CY2020	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	81609000	USD
CY2021	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	108435000	USD
CY2020	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	81018000	USD
CY2021	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	4044000	USD
CY2020	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	2899000	USD
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-15000	USD
CY2020	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-383000	USD
CY2021	fbiz	Gain Loss On Sale Of Community Development Entity GainLossOnSaleOfCommunityDevelopmentEntity	1000	USD
CY2020	fbiz	Gain Loss On Sale Of Community Development Entity GainLossOnSaleOfCommunityDevelopmentEntity	0	USD
CY2021	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	-63000	USD
CY2020	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	-16000	USD
CY2021	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	371000	USD
CY2020	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	0	USD
CY2021	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	-48000	USD
CY2020	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	32000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	1601000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	1557000	USD
CY2021	us-gaap	Proceeds From Lease Payments ProceedsFromLeasePayments	170000	USD
CY2020	us-gaap	Proceeds From Lease Payments ProceedsFromLeasePayments	113000	USD
CY2021	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	6607000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	10837000	USD
CY2021	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	3001000	USD
CY2020	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	4051000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	35992000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	26635000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	51166000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	58290000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	6586000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	6268000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	14955000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	839000	USD
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	93019000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	66879000	USD
CY2021	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	0	USD
CY2020	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	2582000	USD
CY2021	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	86660000	USD
CY2020	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	439223000	USD
CY2021	fbiz	Losson Early Extinguishmentof Debt Financing Activities LossonEarlyExtinguishmentofDebtFinancingActivities	0	USD
CY2020	fbiz	Losson Early Extinguishmentof Debt Financing Activities LossonEarlyExtinguishmentofDebtFinancingActivities	744000	USD
CY2021	fbiz	Payments Of The Federal Paycheck Protection Lending Facility Investing Activities PaymentsOfTheFederalPaycheckProtectionLendingFacilityInvestingActivities	0	USD
CY2021	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	1059000	USD
CY2020	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	1986000	USD
CY2021	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	32000	USD
CY2020	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	211000	USD
CY2021	fbiz	Payments To Acquire Low Income Housing PaymentsToAcquireLowIncomeHousing	2964000	USD
CY2020	fbiz	Payments To Acquire Low Income Housing PaymentsToAcquireLowIncomeHousing	0	USD
CY2021	fbiz	Paymentsto Acquire Historic Development Entities PaymentstoAcquireHistoricDevelopmentEntities	0	USD
CY2020	fbiz	Paymentsto Acquire Historic Development Entities PaymentstoAcquireHistoricDevelopmentEntities	3254000	USD
CY2021	fbiz	Distributionfromhistoricdevelopmententities Distributionfromhistoricdevelopmententities	57000	USD
CY2020	fbiz	Distributionfromhistoricdevelopmententities Distributionfromhistoricdevelopmententities	30000	USD
CY2021	fbiz	Proceedsfrom Saleof Historic Development Entity State Tax Credits ProceedsfromSaleofHistoricDevelopmentEntityStateTaxCredits	0	USD
CY2020	fbiz	Proceedsfrom Saleof Historic Development Entity State Tax Credits ProceedsfromSaleofHistoricDevelopmentEntityStateTaxCredits	2529000	USD
CY2021	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	7439000	USD
CY2020	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	20509000	USD
CY2021	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	7680000	USD
CY2020	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	14884000	USD
CY2021	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	391000	USD
CY2020	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	264000	USD
CY2021	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	44000	USD
CY2020	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	0	USD
CY2021	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	0	USD
CY2020	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	8000000	USD
CY2021	fbiz	Premium Payment On Bank Owned Life Insurance Policies PremiumPaymentOnBankOwnedLifeInsurancePolicies	0	USD
CY2020	fbiz	Premium Payment On Bank Owned Life Insurance Policies PremiumPaymentOnBankOwnedLifeInsurancePolicies	25000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-111012000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-454507000	USD
CY2021	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	102407000	USD
CY2020	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	325137000	USD
CY2021	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	814000000	USD
CY2020	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	1219944000	USD
CY2021	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	788300000	USD
CY2020	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	1318700000	USD
CY2020	fbiz	Payments Of The Federal Paycheck Protection Lending Facility Investing Activities PaymentsOfTheFederalPaycheckProtectionLendingFacilityInvestingActivities	29605000	USD
CY2021	fbiz	Proceedsfromthe Federal Paycheck Protection Program Lending Facility Investing Activities ProceedsfromtheFederalPaycheckProtectionProgramLendingFacilityInvestingActivities	0	USD
CY2020	fbiz	Proceedsfromthe Federal Paycheck Protection Program Lending Facility Investing Activities ProceedsfromtheFederalPaycheckProtectionProgramLendingFacilityInvestingActivities	29605000	USD
CY2021	us-gaap	Proceeds From Repayments Of Notes Payable ProceedsFromRepaymentsOfNotesPayable	9998000	USD
CY2020	us-gaap	Proceeds From Repayments Of Notes Payable ProceedsFromRepaymentsOfNotesPayable	300000	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6166000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	5652000	USD
CY2021	fbiz	Proceeds From Issuance Of Common Stock Under The Employee Stock Purchase Plan ProceedsFromIssuanceOfCommonStockUnderTheEmployeeStockPurchasePlan	160000	USD
CY2020	fbiz	Proceeds From Issuance Of Common Stock Under The Employee Stock Purchase Plan ProceedsFromIssuanceOfCommonStockUnderTheEmployeeStockPurchasePlan	66000	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	5478000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1672000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	75221000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	417679000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	201000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-10193000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	56909000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	67102000	USD
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	57110000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	56909000	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	13206000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	18412000	USD
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	14519000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	3451000	USD
CY2021	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	146000	USD
CY2020	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	80000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	316000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	190000	USD
CY2021	us-gaap	Use Of Estimates UseOfEstimates	Management of the Corporation is required to make estimates and assumptions which affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as reported amounts of revenues and expenses during the reporting period. Actual results could differ significantly from those estimates. Material estimates that could significantly change in the near-term include the value of securities and interest rate swaps, level of the allowance for loan and lease losses, lease residuals, property under operating leases, goodwill, level of the Small Business Administration (“SBA”) recourse reserve, and income taxes.
CY2021	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	Certain amounts in prior periods may have been reclassified to conform to the current presentation.
CY2021Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	3600000	USD
CY2020Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	8700000	USD
CY2021Q4	fbiz	Bank Owned Life Insurance Death Benefits BankOwnedLifeInsuranceDeathBenefits	135900000	USD
CY2020Q4	fbiz	Bank Owned Life Insurance Death Benefits BankOwnedLifeInsuranceDeathBenefits	136100000	USD
CY2021Q4	fbiz	Borrowings Against Cash Surrender Value Of Bank Owned Life Insurance BorrowingsAgainstCashSurrenderValueOfBankOwnedLifeInsurance	0	USD
CY2020Q4	fbiz	Borrowings Against Cash Surrender Value Of Bank Owned Life Insurance BorrowingsAgainstCashSurrenderValueOfBankOwnedLifeInsurance	0	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	13300000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	13600000	USD
CY2021	fbiz	Maximum Ownership Percentage That Is Not Consolidated MaximumOwnershipPercentageThatIsNotConsolidated	0.50
CY2021	fbiz	Investment In Corporations Minimum Ownership Percentage For Accounting For Using Equity Method InvestmentInCorporationsMinimumOwnershipPercentageForAccountingForUsingEquityMethod	0.20
CY2021	fbiz	Investment In Corporations Maximum Ownership Percentage For Accounting For At Cost InvestmentInCorporationsMaximumOwnershipPercentageForAccountingForAtCost	0.20
CY2021	fbiz	Investment In Limited Partnerships Maximum Ownership Percentage For Accounting For At Cost InvestmentInLimitedPartnershipsMaximumOwnershipPercentageForAccountingForAtCost	0.03
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	29000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-4000	USD
CY2021Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	9700000	USD
CY2020Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	29500000	USD
CY2021Q4	fbiz	Balances Held At Federal Reserve BalancesHeldAtFederalReserve	47000000	USD
CY2020Q4	fbiz	Balances Held At Federal Reserve BalancesHeldAtFederalReserve	26700000	USD
CY2021Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	47400000	USD
CY2020Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	27400000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	205699000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	2072000	USD
CY2020Q4	fbiz	Loan Participations Purchased On Corporations Balance Sheet LoanParticipationsPurchasedOnCorporationsBalanceSheet	410000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	2069000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	205702000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	179581000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	4476000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	132000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	183925000	USD
CY2021Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	19746000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	533000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	3000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	20276000	USD
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	26374000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	974000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	15000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	27333000	USD
CY2021	fbiz	Numberofavailableforsalesecuritiessold Numberofavailableforsalesecuritiessold	7	securities
CY2020	fbiz	Numberofavailableforsalesecuritiessold Numberofavailableforsalesecuritiessold	1	securities
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	92000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	0	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	63000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	4000	USD
CY2021	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	29000	USD
CY2020	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-4000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	14955000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	839000	USD
CY2021Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities Pledged PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged	70300000	USD
CY2020Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities Pledged PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged	73700000	USD
CY2020Q4	fbiz	Sba Paycheck Protection Program Loans Outstanding Gross Amount SBAPaycheckProtectionProgramLoansOutstandingGrossAmount	228900000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	2701000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	2724000	USD
CY2021Q4	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	3793000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	3808000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	11887000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	11937000	USD
CY2021Q4	fbiz	Heldtomaturity Securities Debt Maturities Rolling Years Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearsTwoThroughFiveAmortizedCost	7289000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	7391000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	58270000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	58470000	USD
CY2021Q4	fbiz	Heldtomaturity Securities Debt Maturities Rolling Years Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearsSixThroughTenAmortizedCost	7223000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	7576000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	132841000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	132571000	USD
CY2021Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	1441000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	1501000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	205699000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	205702000	USD
CY2021Q4	fbiz	Paycheck Protection Loans And Leases Receivable Deferred Income PaycheckProtectionLoansAndLeasesReceivableDeferredIncome	557000	USD
CY2021Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	19746000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	20276000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	46	securities
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	3	securities
CY2020	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2021	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	100580000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1826000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	6662000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	243000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	107242000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	2069000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	33543000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	98000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	4031000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	34000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	37574000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	132000	USD
CY2021Q4	us-gaap	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions	1	securities
CY2021Q4	fbiz	Heldto Maturity Securities Securitiesin Unrealized Loss Positions Qualitative Disclosures Numberof Positions12monthsorgreater HeldtoMaturitySecuritiesSecuritiesinUnrealizedLossPositionsQualitativeDisclosuresNumberofPositions12monthsorgreater	1	securities
CY2021	us-gaap	Other Than Temporary Impairment Losses Investments Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsHeldtomaturitySecurities	0	USD
CY2020	us-gaap	Other Than Temporary Impairment Losses Investments Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsHeldtomaturitySecurities	0	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2240931000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2150515000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	24336000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	28521000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	1523000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	4545000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	2215072000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	2117449000	USD
CY2021Q4	fbiz	Sba Paycheck Protection Program Loans Outstanding Gross Amount SBAPaycheckProtectionProgramLoansOutstandingGrossAmount	27900000	USD
CY2020Q4	fbiz	Paycheck Protection Loans And Leases Receivable Deferred Income PaycheckProtectionLoansAndLeasesReceivableDeferredIncome	3500000	USD
CY2021Q4	fbiz	Small Business Administration7a Loans SmallBusinessAdministration7aLoans	33223000	USD
CY2020Q4	fbiz	Small Business Administration7a Loans SmallBusinessAdministration7aLoans	36266000	USD
CY2021Q4	fbiz	Small Business Administration504 Loans SmallBusinessAdministration504Loans	41394000	USD
CY2020Q4	fbiz	Small Business Administration504 Loans SmallBusinessAdministration504Loans	26327000	USD
CY2021Q4	fbiz	Small Business Administration Express Loans SmallBusinessAdministrationExpressLoans	387000	USD
CY2020Q4	fbiz	Small Business Administration Express Loans SmallBusinessAdministrationExpressLoans	1251000	USD
CY2021Q4	fbiz	Small Business Administration Paycheck Protection Program Loans SmallBusinessAdministrationPaycheckProtectionProgramLoans	27854000	USD
CY2020Q4	fbiz	Small Business Administration Paycheck Protection Program Loans SmallBusinessAdministrationPaycheckProtectionProgramLoans	228870000	USD
CY2021Q4	fbiz	Small Business Administration Loans SmallBusinessAdministrationLoans	102858000	USD
CY2020Q4	fbiz	Small Business Administration Loans SmallBusinessAdministrationLoans	292714000	USD
CY2021Q4	fbiz	Sb Aloansintheparticipationsoldportfolioconsideredimpaired SBAloansintheparticipationsoldportfolioconsideredimpaired	1700000	USD
CY2020Q4	fbiz	Sb Aloansintheparticipationsoldportfolioconsideredimpaired SBAloansintheparticipationsoldportfolioconsideredimpaired	9300000	USD
CY2021	fbiz	Guaranteed Portionof Sba Loans Soldto Third Parties Total GuaranteedPortionofSBALoansSoldtoThirdPartiesTotal	33500000	USD
CY2020	fbiz	Guaranteed Portionof Sba Loans Soldto Third Parties Total GuaranteedPortionofSBALoansSoldtoThirdPartiesTotal	29200000	USD
CY2021Q4	fbiz	Totalamountofoutstanding Sb Aloanssold TotalamountofoutstandingSBAloanssold	93000000	USD
CY2020Q4	fbiz	Totalamountofoutstanding Sb Aloanssold TotalamountofoutstandingSBAloanssold	79500000	USD
CY2021	fbiz	Loans And Leases Transferred To Third Parties Total Principal Amount LoansAndLeasesTransferredToThirdPartiesTotalPrincipalAmount	70900000	USD
CY2021Q4	fbiz	Loans And Leases Transferred To Third Parties Total Principal Amount LoansAndLeasesTransferredToThirdPartiesTotalPrincipalAmount	48900000	USD
CY2021	fbiz	Gain Loss Recognizedon Participation Interestin Originated Loans GainLossRecognizedonParticipationInterestinOriginatedLoans	0	USD
CY2021Q4	fbiz	Total Amount Of Outstanding Loans Transferred To Third Parties As Loan Participations TotalAmountOfOutstandingLoansTransferredToThirdPartiesAsLoanParticipations	195200000	USD
CY2020Q4	fbiz	Total Amount Of Outstanding Loans Transferred To Third Parties As Loan Participations TotalAmountOfOutstandingLoansTransferredToThirdPartiesAsLoanParticipations	153600000	USD
CY2021Q4	fbiz	Total Amount Of Loan Participations Remaining On Corporations Balance Sheet TotalAmountOfLoanParticipationsRemainingOnCorporationsBalanceSheet	314500000	USD
CY2020Q4	fbiz	Total Amount Of Loan Participations Remaining On Corporations Balance Sheet TotalAmountOfLoanParticipationsRemainingOnCorporationsBalanceSheet	276500000	USD
CY2021Q4	fbiz	Loans In Participation Sold Portfolio Considered Impaired LoansInParticipationSoldPortfolioConsideredImpaired	0	USD
CY2020Q4	fbiz	Loans In The Participation Sold Portfolio Considered Impaired Gross Amount LoansInTheParticipationSoldPortfolioConsideredImpairedGrossAmount	3000000	USD
CY2020Q4	fbiz	Loans In The Participation Sold Portfolio Considered Impaired Sold Amount LoansInTheParticipationSoldPortfolioConsideredImpairedSoldAmount	4200000	USD
CY2021Q4	fbiz	Loan Participations Purchased On Corporations Balance Sheet LoanParticipationsPurchasedOnCorporationsBalanceSheet	0	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1632000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1683000	USD
CY2021	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	570000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	325000	USD
CY2021	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	914000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	376000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1288000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1632000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2240931000	USD
CY2021Q4	fbiz	Category Rating As Percentage Of Total Loans And Leases CategoryRatingAsPercentageOfTotalLoansAndLeases	1.0000
CY2020Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2150515000	USD
CY2020Q4	fbiz	Category Rating As Percentage Of Total Loans And Leases CategoryRatingAsPercentageOfTotalLoansAndLeases	1.0000
CY2021Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2240931000	USD
CY2021Q4	fbiz	Financing Receivable Recorded Investment30 To59 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestment30To59DaysPastDuePercentOfPortfolio	0.0009
CY2021Q4	fbiz	Financing Receivable Recorded Investment60 To89 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestment60To89DaysPastDuePercentOfPortfolio	0.0003
CY2021Q4	fbiz	Financing Receivable Recorded Investment Equal To Greater Than90 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDuePercentOfPortfolio	0.0007
CY2021Q4	fbiz	Financing Receivable Recorded Investment Past Due Percent Of Portfolio FinancingReceivableRecordedInvestmentPastDuePercentOfPortfolio	0.0019
CY2021Q4	fbiz	Financing Receivable Recorded Investment Current Percent Of Portfolio FinancingReceivableRecordedInvestmentCurrentPercentOfPortfolio	0.9981
CY2021Q4	fbiz	Financing Receivable Recorded Investment Gross Percent Of Portfolio FinancingReceivableRecordedInvestmentGrossPercentOfPortfolio	1.0000
CY2020Q4	us-gaap	Loans And Leases Receivable Before Fees Gross LoansAndLeasesReceivableBeforeFeesGross	2150515000	USD
CY2020Q4	fbiz	Financing Receivable Recorded Investment30 To59 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestment30To59DaysPastDuePercentOfPortfolio	0.0044
CY2020Q4	fbiz	Financing Receivable Recorded Investment60 To89 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestment60To89DaysPastDuePercentOfPortfolio	0.0002
CY2020Q4	fbiz	Financing Receivable Recorded Investment Equal To Greater Than90 Days Past Due Percent Of Portfolio FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDuePercentOfPortfolio	0.0054
CY2020Q4	fbiz	Financing Receivable Recorded Investment Past Due Percent Of Portfolio FinancingReceivableRecordedInvestmentPastDuePercentOfPortfolio	0.0100
CY2020Q4	fbiz	Financing Receivable Recorded Investment Current Percent Of Portfolio FinancingReceivableRecordedInvestmentCurrentPercentOfPortfolio	0.9900
CY2020Q4	fbiz	Financing Receivable Recorded Investment Gross Percent Of Portfolio FinancingReceivableRecordedInvestmentGrossPercentOfPortfolio	1.0000
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	6358000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	26617000	USD
CY2021Q4	us-gaap	Foreclosed Assets ForeclosedAssets	164000	USD
CY2020Q4	us-gaap	Foreclosed Assets ForeclosedAssets	34000	USD
CY2021Q4	fbiz	Total Nonperforming Assets TotalNonperformingAssets	6522000	USD
CY2020Q4	fbiz	Total Nonperforming Assets TotalNonperformingAssets	26651000	USD
CY2021Q4	fbiz	Financing Receivable Modifications Performing Troubled Debt Restructuring FinancingReceivableModificationsPerformingTroubledDebtRestructuring	217000	USD
CY2020Q4	fbiz	Financing Receivable Modifications Performing Troubled Debt Restructuring FinancingReceivableModificationsPerformingTroubledDebtRestructuring	46000	USD
CY2021Q4	fbiz	Impaired Assets ImpairedAssets	6739000	USD
CY2020Q4	fbiz	Impaired Assets ImpairedAssets	26697000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Ratio Of Nonperforming Loans To All Loans LoansAndLeasesReceivableRatioOfNonperformingLoansToAllLoans	0.0028
CY2020Q4	us-gaap	Loans And Leases Receivable Ratio Of Nonperforming Loans To All Loans LoansAndLeasesReceivableRatioOfNonperformingLoansToAllLoans	0.0124
CY2021Q4	fbiz	Ratio Of Total Nonperforming Assets To Gross Loans And Leases Plus Foreclosed Properties Net RatioOfTotalNonperformingAssetsToGrossLoansAndLeasesPlusForeclosedPropertiesNet	0.0029
CY2020Q4	fbiz	Ratio Of Total Nonperforming Assets To Gross Loans And Leases Plus Foreclosed Properties Net RatioOfTotalNonperformingAssetsToGrossLoansAndLeasesPlusForeclosedPropertiesNet	0.0124
CY2021Q4	fbiz	Ratio Of Total Nonperforming Assets To Total Assets RatioOfTotalNonperformingAssetsToTotalAssets	0.0025
CY2020Q4	fbiz	Ratio Of Total Nonperforming Assets To Total Assets RatioOfTotalNonperformingAssetsToTotalAssets	0.0104
CY2021Q4	fbiz	Ratio Of Allowance For Loan And Lease Losses To Total Gross Loans And Leases RatioOfAllowanceForLoanAndLeaseLossesToTotalGrossLoansAndLeases	0.0109
CY2020Q4	fbiz	Ratio Of Allowance For Loan And Lease Losses To Total Gross Loans And Leases RatioOfAllowanceForLoanAndLeaseLossesToTotalGrossLoansAndLeases	0.0133
CY2021Q4	fbiz	Ratio Of Allowance For Loan And Leases Losses To Non Accrual Loans And Leases RatioOfAllowanceForLoanAndLeasesLossesToNonAccrualLoansAndLeases	3.8276
CY2020Q4	fbiz	Ratio Of Allowance For Loan And Leases Losses To Non Accrual Loans And Leases RatioOfAllowanceForLoanAndLeasesLossesToNonAccrualLoansAndLeases	1.0715
CY2021Q4	fbiz	Non Accrual Troubled Debt Restructurings NonAccrualTroubledDebtRestructurings	627000	USD
CY2020Q4	fbiz	Non Accrual Troubled Debt Restructurings NonAccrualTroubledDebtRestructurings	6500000	USD
CY2021Q4	fbiz	Specific Reserveson Troubled Debt Restructurings SpecificReservesonTroubledDebtRestructurings	134000	USD
CY2020Q4	fbiz	Specific Reserveson Troubled Debt Restructurings SpecificReservesonTroubledDebtRestructurings	760000	USD
CY2021Q4	fbiz	Unfunded Commitments Troubled Debt Restructurings UnfundedCommitmentsTroubledDebtRestructurings	0	USD
CY2021	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	3	loans
CY2021	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	239000	USD
CY2021	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	217000	USD
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	6	loans
CY2020	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	6585000	USD
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	1167000	USD
CY2021Q4	fbiz	Numberof Short Term Loan Modifications NumberofShortTermLoanModifications	3	loans
CY2020Q4	fbiz	Numberof Short Term Loan Modifications NumberofShortTermLoanModifications	38	loans
CY2021Q4	fbiz	Gross Loansand Leases Outstanding Short Term Modification GrossLoansandLeasesOutstandingShortTermModification	293000	USD
CY2020Q4	fbiz	Gross Loansand Leases Outstanding Short Term Modification GrossLoansandLeasesOutstandingShortTermModification	27000000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	4419000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	4564000	USD
CY2021	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	12754000	USD
CY2021	fbiz	Impaired Financing Receivable With No Related Allowance Foregone Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceForegoneInterestIncome	991000	USD
CY2021	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	446000	USD
CY2021	fbiz	Impaired Financing Receivable With No Related Allowance Net Foregone Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceNetForegoneInterestIncome	545000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	2156000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	2156000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1505000	USD
CY2021	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	1506000	USD
CY2021	fbiz	Impaired Financing Receivable With Related Allowance Foregone Interest Income ImpairedFinancingReceivableWithRelatedAllowanceForegoneInterestIncome	113000	USD
CY2021	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	8000	USD
CY2021	fbiz	Impaired Financing Receivable With Related Allowance Net Foregone Interest Income ImpairedFinancingReceivableWithRelatedAllowanceNetForegoneInterestIncome	105000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	6575000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	6720000	USD
CY2021Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1505000	USD
CY2021	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	14260000	USD
CY2021	fbiz	Impaired Financing Receivable Foregone Interest Income ImpairedFinancingReceivableForegoneInterestIncome	1104000	USD
CY2021	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	454000	USD
CY2021	fbiz	Impaired Financing Receivable Net Foregone Interest Income ImpairedFinancingReceivableNetForegoneInterestIncome	650000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	18966000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	29191000	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	21709000	USD
CY2020	fbiz	Impaired Financing Receivable With No Related Allowance Foregone Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceForegoneInterestIncome	2082000	USD
CY2020	us-gaap	Impaired Financing Receivable With No Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod	636000	USD
CY2020	fbiz	Impaired Financing Receivable With No Related Allowance Net Foregone Interest Income ImpairedFinancingReceivableWithNoRelatedAllowanceNetForegoneInterestIncome	1446000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	7697000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	12103000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	3681000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	5994000	USD
CY2020	fbiz	Impaired Financing Receivable With Related Allowance Foregone Interest Income ImpairedFinancingReceivableWithRelatedAllowanceForegoneInterestIncome	712000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Cash Basis Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod	0	USD
CY2020	fbiz	Impaired Financing Receivable With Related Allowance Net Foregone Interest Income ImpairedFinancingReceivableWithRelatedAllowanceNetForegoneInterestIncome	712000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	26663000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	41294000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	3681000	USD
CY2020	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	27703000	USD
CY2020	fbiz	Impaired Financing Receivable Foregone Interest Income ImpairedFinancingReceivableForegoneInterestIncome	2794000	USD
CY2020	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	636000	USD
CY2020	fbiz	Impaired Financing Receivable Net Foregone Interest Income ImpairedFinancingReceivableNetForegoneInterestIncome	2158000	USD
CY2021Q4	fbiz	Loans And Leases Receivable Difference Between Recorded Investment And Unpaid Principal Balance LoansAndLeasesReceivableDifferenceBetweenRecordedInvestmentAndUnpaidPrincipalBalance	145000	USD
CY2020Q4	fbiz	Loans And Leases Receivable Difference Between Recorded Investment And Unpaid Principal Balance LoansAndLeasesReceivableDifferenceBetweenRecordedInvestmentAndUnpaidPrincipalBalance	14600000	USD
CY2021Q4	fbiz	Financing Receivable Modifications Performing Troubled Debt Restructuring FinancingReceivableModificationsPerformingTroubledDebtRestructuring	217000	USD
CY2020Q4	fbiz	Financing Receivable Modifications Performing Troubled Debt Restructuring FinancingReceivableModificationsPerformingTroubledDebtRestructuring	46000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	28521000	USD
CY2021	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	3508000	USD
CY2021	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	5126000	USD
CY2021	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	1618000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-5803000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	24336000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	19520000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	8139000	USD
CY2020	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	332000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	-7807000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	16808000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	28521000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	22831000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1505000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	24336000	USD
CY2021Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	2234356000	USD
CY2021Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	6575000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	2240931000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	24840000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	3681000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	28521000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	2123852000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	26663000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	2150515000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived	13641000	USD
CY2020Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived	19106000	USD
CY2021Q4	us-gaap	Direct Financing Lease Unguaranteed Residual Asset DirectFinancingLeaseUnguaranteedResidualAsset	3564000	USD
CY2020Q4	us-gaap	Direct Financing Lease Unguaranteed Residual Asset DirectFinancingLeaseUnguaranteedResidualAsset	5434000	USD
CY2021Q4	us-gaap	Direct Financing Lease Deferred Selling Profit DirectFinancingLeaseDeferredSellingProfit	1462000	USD
CY2020Q4	us-gaap	Direct Financing Lease Deferred Selling Profit DirectFinancingLeaseDeferredSellingProfit	2209000	USD
CY2021Q4	us-gaap	Direct Financing Lease Net Investment In Lease DirectFinancingLeaseNetInvestmentInLease	15743000	USD
CY2020Q4	us-gaap	Direct Financing Lease Net Investment In Lease DirectFinancingLeaseNetInvestmentInLease	22331000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Next Rolling Twelve Months SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextRollingTwelveMonths	5381000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Lease Payments To Be Received Rolling Year Two SalesTypeAndDirectFinancingLeasesLeaseReceivableLeasePaymentsToBeReceivedRollingYearTwo	3998000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Lease Payments To Be Received Rolling Year Three SalesTypeAndDirectFinancingLeasesLeaseReceivableLeasePaymentsToBeReceivedRollingYearThree	2526000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received Rolling Year Four SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRollingYearFour	1246000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Lease Payments To Be Received Rolling Year Five SalesTypeAndDirectFinancingLeasesLeaseReceivableLeasePaymentsToBeReceivedRollingYearFive	349000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Lease Payments To Be Received After Rolling Year Five SalesTypeAndDirectFinancingLeasesLeaseReceivableLeasePaymentsToBeReceivedAfterRollingYearFive	141000	USD
CY2021Q4	us-gaap	Sales Type And Direct Financing Leases Lease Receivable Payments To Be Received SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived	13641000	USD
CY2021	us-gaap	Depreciation Depreciation	585000	USD
CY2021Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	2727000	USD
CY2020Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	2670000	USD
CY2021Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	6824000	USD
CY2020Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	6961000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	9551000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	9631000	USD
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	7857000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	7633000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1694000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1998000	USD
CY2020	us-gaap	Depreciation Depreciation	822000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	316000	USD
CY2021	fbiz	Right Of Use Asset Obtained In Exchange For Operating Lease Liability New Operating Leases During The Year RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityNewOperatingLeasesDuringTheYear	117000	USD
CY2021	us-gaap	Operating Lease Expense OperatingLeaseExpense	1513000	USD
CY2020	us-gaap	Operating Lease Expense OperatingLeaseExpense	1494000	USD
CY2021	us-gaap	Short Term Lease Cost ShortTermLeaseCost	158000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	222000	USD
CY2021	us-gaap	Variable Lease Cost VariableLeaseCost	492000	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	522000	USD
CY2021	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	170000	USD
CY2020	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	113000	USD
CY2021	us-gaap	Lease Cost LeaseCost	1993000	USD
CY2020	us-gaap	Lease Cost LeaseCost	2125000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y18D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y9M18D
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0251
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0303
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	1628000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	1103000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	816000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	666000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	646000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	996000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	5855000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	449000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	5406000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	10700000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	10700000	USD
CY2021	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	412000	USD
CY2020	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	458000	USD
CY2021Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	1600000	USD
CY2020Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	1300000	USD
CY2021Q4	fbiz	Investmentin Historic Development Entities InvestmentinHistoricDevelopmentEntities	2300000	USD
CY2020Q4	fbiz	Investmentin Historic Development Entities InvestmentinHistoricDevelopmentEntities	2400000	USD
CY2020	fbiz	Capital Contributionsto Historic Rehabilitation Tax Credits CapitalContributionstoHistoricRehabilitationTaxCredits	4400000	USD
CY2020	fbiz	Tax Credit Benefits Recognizedon Federal Historic Tax Credits TaxCreditBenefitsRecognizedonFederalHistoricTaxCredits	2800000	USD
CY2020	fbiz	Impairment On Investment In Historic Rehabilitation Tax Credits ImpairmentOnInvestmentInHistoricRehabilitationTaxCredits	1900000	USD
CY2020	fbiz	Tax Credit Benefits Recognized On State Historic Tax Credits TaxCreditBenefitsRecognizedOnStateHistoricTaxCredits	2700000	USD
CY2020	fbiz	Gainon Saleof Historic Development Entities GainonSaleofHistoricDevelopmentEntities	275000	USD
CY2021Q4	fbiz	Investment In Low Income Housing InvestmentInLowIncomeHousing	3000000	USD
CY2021Q4	fbiz	Capital Contributions To Low Income Housing Tax Credits CapitalContributionsToLowIncomeHousingTaxCredits	3000000	USD
CY2021Q4	fbiz	Investmentin Community Development Entities InvestmentinCommunityDevelopmentEntities	0	USD
CY2020Q4	fbiz	Investmentin Community Development Entities InvestmentinCommunityDevelopmentEntities	5300000	USD
CY2020	fbiz	Tax Credit Benefits Recognizedon New Market Tax Credits TaxCreditBenefitsRecognizedonNewMarketTaxCredits	450000	USD
CY2021	fbiz	Tax Credit Benefits Recognizedon New Market Tax Credits TaxCreditBenefitsRecognizedonNewMarketTaxCredits	450000	USD
CY2021	fbiz	Incomefrom Equity Method Investments IncomefromEquityMethodInvestments	2500000	USD
CY2021Q4	fbiz	Incomefrom Equity Method Investments IncomefromEquityMethodInvestments	520000	USD
CY2021	fbiz	Losson Equity Method Investments LossonEquityMethodInvestments	24000	USD
CY2021Q4	fbiz	Losson Equity Method Investments LossonEquityMethodInvestments	99000	USD
CY2021Q4	fbiz	Investmentin Trust Ii InvestmentinTrustII	315000	USD
CY2021Q4	us-gaap	Interest Receivable InterestReceivable	5497000	USD
CY2020Q4	us-gaap	Interest Receivable InterestReceivable	8564000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	6175000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	7217000	USD
CY2021Q4	fbiz	Investmentin Historic Development Entities InvestmentinHistoricDevelopmentEntities	2299000	USD
CY2020Q4	fbiz	Investmentin Historic Development Entities InvestmentinHistoricDevelopmentEntities	2356000	USD
CY2021Q4	fbiz	Investment In Low Income Housing InvestmentInLowIncomeHousing	2964000	USD
CY2020Q4	fbiz	Investment In Low Income Housing InvestmentInLowIncomeHousing	0	USD
CY2021Q4	fbiz	Investmentin Community Development Entities InvestmentinCommunityDevelopmentEntities	0	USD
CY2020Q4	fbiz	Investmentin Community Development Entities InvestmentinCommunityDevelopmentEntities	5306000	USD
CY2021Q4	fbiz	Investmentin Limited Partnerships InvestmentinLimitedPartnerships	9874000	USD
CY2020Q4	fbiz	Investmentin Limited Partnerships InvestmentinLimitedPartnerships	6673000	USD
CY2021Q4	fbiz	Investmentin Trust Ii InvestmentinTrustII	315000	USD
CY2020Q4	fbiz	Investmentin Trust Ii InvestmentinTrustII	315000	USD
CY2021Q4	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	2689000	USD
CY2020Q4	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	2165000	USD
CY2021Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	9577000	USD
CY2020Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	6882000	USD
CY2021Q4	us-gaap	Other Assets OtherAssets	39390000	USD
CY2020Q4	us-gaap	Other Assets OtherAssets	39478000	USD
CY2021Q4	us-gaap	Deposits Deposits	1957923000	USD
CY2021	fbiz	Average Balance Deposits AverageBalanceDeposits	1904133000	USD
CY2021	fbiz	Deposits Weighted Average Interest Rate Duringthe Period DepositsWeightedAverageInterestRateDuringthePeriod	0.0019
CY2020Q4	us-gaap	Deposits Deposits	1855516000	USD
CY2020	fbiz	Average Balance Deposits AverageBalanceDeposits	1711092000	USD
CY2020	fbiz	Deposits Weighted Average Interest Rate Duringthe Period DepositsWeightedAverageInterestRateDuringthePeriod	0.0052
CY2021Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	68020000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	4548000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	349000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	324000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	488000	USD
CY2021Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	0	USD
CY2021Q4	us-gaap	Time Deposits TimeDeposits	73729000	USD
CY2021Q4	fbiz	Time Deposits250000or More TimeDeposits250000orMore	7900000	USD
CY2020Q4	fbiz	Time Deposits250000or More TimeDeposits250000orMore	28700000	USD
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	413527000	USD
CY2021	fbiz	Borrowed Funds Average Balance BorrowedFundsAverageBalance	418783000	USD
CY2021	us-gaap	Debt Instrument Interest Rate During Period DebtInstrumentInterestRateDuringPeriod	0.0186
CY2020Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	429229000	USD
CY2020	fbiz	Borrowed Funds Average Balance BorrowedFundsAverageBalance	429624000	USD
CY2020	us-gaap	Debt Instrument Interest Rate During Period DebtInstrumentInterestRateDuringPeriod	0.0191
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	173500000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	37300000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	35500000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	23363000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	143864000	USD
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	413527000	USD
CY2021Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Loans Receivable Pledged For Federal Home Loan Bank Debt PledgedFinancialInstrumentsNotSeparatelyReportedLoansReceivablePledgedForFederalHomeLoanBankDebt	1305000000	USD
CY2020Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Loans Receivable Pledged For Federal Home Loan Bank Debt PledgedFinancialInstrumentsNotSeparatelyReportedLoansReceivablePledgedForFederalHomeLoanBankDebt	1219000000	USD
CY2021	us-gaap	Line Of Credit Facility Commitment Fee Amount LineOfCreditFacilityCommitmentFeeAmount	13000	USD
CY2021Q4	us-gaap	Subordinated Debt SubordinatedDebt	23800000	USD
CY2021Q4	fbiz	Unamortized Debt Issuance Cost Subordinated Notes UnamortizedDebtIssuanceCostSubordinatedNotes	302000	USD
CY2008Q3	us-gaap	Debt Instrument Interest Rate Stated Percentage DebtInstrumentInterestRateStatedPercentage	0.1050
CY2021Q4	fbiz	Sole Ownership Of Common Securities Issued By Trust Ii SoleOwnershipOfCommonSecuritiesIssuedByTrustIi	315000	USD
CY2008Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	10300000	USD
CY2021Q4	us-gaap	Debt Instrument Interest Rate Stated Percentage DebtInstrumentInterestRateStatedPercentage	0.1050
CY2021Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	239000	USD
CY2021	us-gaap	Description Of Material Affects Of Noncompliance DescriptionOfMaterialAffectsOfNoncompliance	Failure to meet minimum capital requirements can result in certain mandatory, and possibly additional discretionary actions on the part of regulators, that if undertaken, could have a direct material effect on the Bank’s assets, liabilities, and certain off-balance sheet items as calculated under regulatory practices.
CY2021Q4	us-gaap	Capital Capital	281745000	USD
CY2021Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1082
CY2021Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	208337000	USD
CY2021Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2021Q4	fbiz	Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer CapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	273443000	USD
CY2021Q4	fbiz	Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets CapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.1050
CY2021Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	232795000	USD
CY2021Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.0894
CY2021Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	156253000	USD
CY2021Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2021Q4	fbiz	Tier One Risk Based Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	221358000	USD
CY2021Q4	fbiz	Tier One Risk Based Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0850
CY2021Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	222719000	USD
CY2021Q4	fbiz	Common Equity Tier One Capitalto Risk Weighted Assets CommonEquityTierOneCapitaltoRiskWeightedAssets	0.0855
CY2021Q4	us-gaap	Common Equity Tier One Capital Required For Capital Adequacy CommonEquityTierOneCapitalRequiredForCapitalAdequacy	117190000	USD
CY2021Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacyto Risk Weighted Assets CommonEquityTierOneCapitalRequiredforCapitalAdequacytoRiskWeightedAssets	0.0450
CY2021Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	182295000	USD
CY2021Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0700
CY2021Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	232795000	USD
CY2021Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0894
CY2021Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	104145000	USD
CY2021Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2021Q4	fbiz	Tier One Leverage Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer TierOneLeverageCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	104145000	USD
CY2021Q4	fbiz	Tier One Leverage Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets TierOneLeverageCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0400
CY2020Q4	us-gaap	Capital Capital	258607000	USD
CY2020Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1125
CY2020Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	183965000	USD
CY2020Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2020Q4	fbiz	Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer CapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	241454000	USD
CY2020Q4	fbiz	Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets CapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.1050
CY2020Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	206104000	USD
CY2020Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.0896
CY2020Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	137974000	USD
CY2020Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2020Q4	fbiz	Tier One Risk Based Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	195463000	USD
CY2020Q4	fbiz	Tier One Risk Based Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0850
CY2020Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	196042000	USD
CY2020Q4	fbiz	Common Equity Tier One Capitalto Risk Weighted Assets CommonEquityTierOneCapitaltoRiskWeightedAssets	0.0853
CY2020Q4	us-gaap	Common Equity Tier One Capital Required For Capital Adequacy CommonEquityTierOneCapitalRequiredForCapitalAdequacy	103480000	USD
CY2020Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacyto Risk Weighted Assets CommonEquityTierOneCapitalRequiredforCapitalAdequacytoRiskWeightedAssets	0.0450
CY2020Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	160970000	USD
CY2020Q4	fbiz	Common Equity Tier One Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0700
CY2020Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	206104000	USD
CY2020Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0799
CY2020Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	103228000	USD
CY2020Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2020Q4	fbiz	Tier One Leverage Capital Requiredfor Capital Adequacy Plus Capital Conservation Buffer TierOneLeverageCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer	103228000	USD
CY2020Q4	fbiz	Tier One Leverage Capital Requiredfor Capital Adequacy Plus Conservation Bufferto Risk Weighted Assets TierOneLeverageCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets	0.0400
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	232422000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	206162000	USD
CY2021Q4	us-gaap	Aoci Before Tax Attributable To Parent AociBeforeTaxAttributableToParent	1457000	USD
CY2020Q4	us-gaap	Aoci Before Tax Attributable To Parent AociBeforeTaxAttributableToParent	933000	USD
CY2021Q4	fbiz	Disallowed Servicing Assetsand Purchased Credit Card Relationships DisallowedServicingAssetsandPurchasedCreditCardRelationships	727000	USD
CY2020Q4	fbiz	Disallowed Servicing Assetsand Purchased Credit Card Relationships DisallowedServicingAssetsandPurchasedCreditCardRelationships	587000	USD
CY2021Q4	fbiz	Disallowed Goodwilland Intangibles DisallowedGoodwillandIntangibles	10433000	USD
CY2020Q4	fbiz	Disallowed Goodwilland Intangibles DisallowedGoodwillandIntangibles	10466000	USD
CY2021Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	10076000	USD
CY2020Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	10062000	USD
CY2021Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	232795000	USD
CY2020Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	206104000	USD
CY2021Q4	fbiz	Allowable General Valuation Allowances And Subordinated Debt AllowableGeneralValuationAllowancesAndSubordinatedDebt	48950000	USD
CY2020Q4	fbiz	Allowable General Valuation Allowances And Subordinated Debt AllowableGeneralValuationAllowancesAndSubordinatedDebt	52503000	USD
CY2021Q4	us-gaap	Capital Capital	281745000	USD
CY2020Q4	us-gaap	Capital Capital	258607000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	35755000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	16978000	USD
CY2021	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	1053000	USD
CY2020	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	423000	USD
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	34702000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	16555000	USD
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	8314921	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	8384464	shares
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.17
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.97
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	34702000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	16555000	USD
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	8314921	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	8384464	shares
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.17
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
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CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	187804	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	24.29
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CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	22.51
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CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	23.57
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CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	25.82
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CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue	22.26
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CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	24.62
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	187804	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	24.29
CY2021Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	3300000	USD
CY2021	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y1M6D
CY2021	us-gaap	Stock Issued During Period Shares Employee Stock Purchase Plans StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans	6532	shares
CY2021Q4	fbiz	Employee Stock Purchase Plan Number Of Shares Available For Grant EmployeeStockPurchasePlanNumberOfSharesAvailableForGrant	239502	shares
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	2513000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	1871000	USD
CY2021	fbiz	Defined Contribution Maximum Annual Matching Contribution Per Employee Percent DefinedContributionMaximumAnnualMatchingContributionPerEmployeePercent	0.03
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CY2021	fbiz	Defined Contribution Plan Employer Matching Contribution DefinedContributionPlanEmployerMatchingContribution	987000	USD
CY2020	fbiz	Defined Contribution Plan Employer Matching Contribution DefinedContributionPlanEmployerMatchingContribution	896000	USD
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CY2020	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	1200000	USD
CY2021	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	237000	USD
CY2020	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	193000	USD
CY2021Q4	us-gaap	Deferred Compensation Cashbased Arrangements Liability Current And Noncurrent DeferredCompensationCashbasedArrangementsLiabilityCurrentAndNoncurrent	1900000	USD
CY2020Q4	us-gaap	Deferred Compensation Cashbased Arrangements Liability Current And Noncurrent DeferredCompensationCashbasedArrangementsLiabilityCurrentAndNoncurrent	1600000	USD
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	6965000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	1948000	USD
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	3087000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1386000	USD
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	10052000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	3334000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	1333000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-1678000	USD
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-110000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-329000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1223000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2007000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11275000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1327000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	6312000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	7276000	USD
CY2021Q4	fbiz	Deferred Tax Assets Tax Deferred Expense Reservesand Accruals Sba Recourse Reserve DeferredTaxAssetsTaxDeferredExpenseReservesandAccrualsSBARecourseReserve	215000	USD
CY2020Q4	fbiz	Deferred Tax Assets Tax Deferred Expense Reservesand Accruals Sba Recourse Reserve DeferredTaxAssetsTaxDeferredExpenseReservesandAccrualsSBARecourseReserve	302000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	2016000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	1457000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	436000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	482000	USD
CY2021Q4	fbiz	Deferred Tax Assets Write Down Of Foreclosed Properties DeferredTaxAssetsWriteDownOfForeclosedProperties	5000	USD
CY2020Q4	fbiz	Deferred Tax Assets Write Down Of Foreclosed Properties DeferredTaxAssetsWriteDownOfForeclosedProperties	0	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	1831000	USD
CY2021Q4	fbiz	Deferred Tax Assets Non Accrual Loan Interest DeferredTaxAssetsNonAccrualLoanInterest	176000	USD
CY2020Q4	fbiz	Deferred Tax Assets Non Accrual Loan Interest DeferredTaxAssetsNonAccrualLoanInterest	820000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	21000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Capital Loss Carryforwards DeferredTaxAssetsCapitalLossCarryforwards	21000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	501000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	319000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	619000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	356000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	10301000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	12864000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	3014000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	4363000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	420000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	358000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	692000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	926000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	4126000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	5647000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	6175000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	7217000	USD
CY2021	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-1042000	USD
CY2020	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	1864000	USD
CY2021	fbiz	Deferred Taxes Allocated To Other Comprehensive Income DeferredTaxesAllocatedToOtherComprehensiveIncome	-181000	USD
CY2020	fbiz	Deferred Taxes Allocated To Other Comprehensive Income DeferredTaxesAllocatedToOtherComprehensiveIncome	143000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1223000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2007000	USD
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CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9876000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	3844000	USD
CY2021	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	2351000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	837000	USD
CY2021	fbiz	Income Tax Reconciliation Tax Exempt Income Tax Exempt Security And Loan Income Net Of Tefra Adjustments IncomeTaxReconciliationTaxExemptIncomeTaxExemptSecurityAndLoanIncomeNetOfTefraAdjustments	710000	USD
CY2020	fbiz	Income Tax Reconciliation Tax Exempt Income Tax Exempt Security And Loan Income Net Of Tefra Adjustments IncomeTaxReconciliationTaxExemptIncomeTaxExemptSecurityAndLoanIncomeNetOfTefraAdjustments	648000	USD
CY2021	fbiz	Income Tax Reconciliation Tax Exempt Income Bank Owned Life Insurance IncomeTaxReconciliationTaxExemptIncomeBankOwnedLifeInsurance	297000	USD
CY2020	fbiz	Income Tax Reconciliation Tax Exempt Income Bank Owned Life Insurance IncomeTaxReconciliationTaxExemptIncomeBankOwnedLifeInsurance	294000	USD
CY2021	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	0	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	2535000	USD
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	55000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	123000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11275000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1327000	USD
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CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
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CY2021Q4	fbiz	Accumulated Derivative Credit Valuation Adjustment AccumulatedDerivativeCreditValuationAdjustment	191000	USD
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CY2021Q4	fbiz	Interest Rate Swaps Default InterestRateSwapsDefault	0	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	3600000	USD
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CY2021Q4	fbiz	Accrued Credit Losses For Financial Instruments With Off Balance Sheet Risk AccruedCreditLossesForFinancialInstrumentsWithOffBalanceSheetRisk	0	USD
CY2020Q4	fbiz	Accrued Credit Losses For Financial Instruments With Off Balance Sheet Risk AccruedCreditLossesForFinancialInstrumentsWithOffBalanceSheetRisk	0	USD
CY2021Q4	fbiz	Sba Loans Probabilityof Future Losses SBALoansProbabilityofFutureLosses	635000	USD
CY2020Q4	fbiz	Sba Loans Probabilityof Future Losses SBALoansProbabilityofFutureLosses	723000	USD
CY2020Q4	fbiz	Sba Recourse Reserve SBARecourseReserve	723000	USD
CY2019Q4	fbiz	Sba Recourse Reserve SBARecourseReserve	1345000	USD
CY2021	fbiz	Sba Recourse Provision SBARecourseProvision	-76000	USD
CY2020	fbiz	Sba Recourse Provision SBARecourseProvision	-278000	USD
CY2021	fbiz	Sba Loan Charge Offs Net SBALoanChargeOffsNet	-12000	USD
CY2020	fbiz	Sba Loan Charge Offs Net SBALoanChargeOffsNet	-344000	USD
CY2021Q4	fbiz	Sba Recourse Reserve SBARecourseReserve	635000	USD
CY2020Q4	fbiz	Sba Recourse Reserve SBARecourseReserve	723000	USD
CY2020	fbiz	Fair Value Liabilities Level1to Level2 Transfers Amount1 FairValueLiabilitiesLevel1toLevel2TransfersAmount1	0	USD
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3	0	USD
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	0	USD
CY2021	fbiz	Fair Value Assets Level1to Level2 Transfers Amount1 FairValueAssetsLevel1toLevel2TransfersAmount1	0	USD
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CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3	0	USD
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CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersIntoLevel3	0	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	0	USD
CY2021	fbiz	Fair Value Assets Level2to Level1 Transfers Amount1 FairValueAssetsLevel2toLevel1TransfersAmount1	0	USD
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Liability Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3	0	USD
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CY2021Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	57110000	USD
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CY2021Q4	fbiz	Federal Home Loan Bank And Other Borrowings Fair Value Disclosure FederalHomeLoanBankAndOtherBorrowingsFairValueDisclosure	409894000	USD
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CY2021Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	8844000	USD
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CY2020Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	56909000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	183925000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	183925000	USD
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CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	27333000	USD
CY2020Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	8695000	USD
CY2020Q4	us-gaap	Loans Held For Sale Fair Value Disclosure LoansHeldForSaleFairValueDisclosure	9478000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	2117449000	USD
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CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	13578000	USD
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CY2020Q4	fbiz	Accrued Interest Receivable Fair Value Disclosure AccruedInterestReceivableFairValueDisclosure	8564000	USD
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CY2020Q4	us-gaap	Deposits Fair Value Disclosure DepositsFairValueDisclosure	1856910000	USD
CY2020Q4	fbiz	Federal Home Loan Bank And Other Borrowings FederalHomeLoanBankAndOtherBorrowings	419167000	USD
CY2020Q4	fbiz	Federal Home Loan Bank And Other Borrowings Fair Value Disclosure FederalHomeLoanBankAndOtherBorrowingsFairValueDisclosure	429347000	USD
CY2020Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	10062000	USD
CY2020Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	9986000	USD
CY2020Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	1578000	USD
CY2020Q4	us-gaap	Accrued Liabilities Fair Value Disclosure AccruedLiabilitiesFairValueDisclosure	1578000	USD
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	75000	USD
CY2020Q4	fbiz	Standby Letters Of Credit Fair Value Disclosure StandbyLettersOfCreditFairValueDisclosure	75000	USD
CY2021	fbiz	Proceeds From Purchases Of Employee Stock Purchase Plan Shares ProceedsFromPurchasesOfEmployeeStockPurchasePlanShares	160000	USD
CY2020	fbiz	Proceeds From Purchases Of Employee Stock Purchase Plan Shares ProceedsFromPurchasesOfEmployeeStockPurchasePlanShares	66000	USD
CY2021Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	23575000	USD
CY2021Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	24014000	USD
CY2021Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	24599000	USD
CY2021Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	23807000	USD
CY2020Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	25770000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	22276000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	22761000	USD
CY2020Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	23372000	USD
CY2021Q4	us-gaap	Interest Expense InterestExpense	2651000	USD
CY2021Q3	us-gaap	Interest Expense InterestExpense	2791000	USD
CY2021Q2	us-gaap	Interest Expense InterestExpense	2947000	USD
CY2021Q1	us-gaap	Interest Expense InterestExpense	2944000	USD
CY2020Q4	us-gaap	Interest Expense InterestExpense	3258000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	3655000	USD
CY2020Q2	us-gaap	Interest Expense InterestExpense	3873000	USD
CY2020Q1	us-gaap	Interest Expense InterestExpense	6322000	USD
CY2021Q4	us-gaap	Noninterest Income NoninterestIncome	7569000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	7015000	USD
CY2021Q2	us-gaap	Noninterest Income NoninterestIncome	6321000	USD
CY2021Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	20924000	USD
CY2021Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	21223000	USD
CY2021Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	21652000	USD
CY2021Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	20863000	USD
CY2020Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	22512000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	18621000	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	18888000	USD
CY2020Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	17050000	USD
CY2021Q4	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-508000	USD
CY2021Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-2269000	USD
CY2021Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-958000	USD
CY2021Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-2068000	USD
CY2020Q4	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	4322000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	3835000	USD
CY2020Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	5469000	USD
CY2020Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	3182000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	12796000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	7338000	USD
CY2021Q1	us-gaap	Noninterest Income NoninterestIncome	7195000	USD
CY2020Q4	us-gaap	Noninterest Income NoninterestIncome	6799000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	7408000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	6319000	USD
CY2020Q1	us-gaap	Noninterest Income NoninterestIncome	6414000	USD
CY2021Q4	us-gaap	Noninterest Expense NoninterestExpense	17531000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	18490000	USD
CY2021Q2	us-gaap	Noninterest Expense NoninterestExpense	18184000	USD
CY2021Q1	us-gaap	Noninterest Expense NoninterestExpense	17330000	USD
CY2020Q4	us-gaap	Noninterest Expense NoninterestExpense	17651000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	16758000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	18343000	USD
CY2020Q1	us-gaap	Noninterest Expense NoninterestExpense	16146000	USD
CY2021Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	11470000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	12017000	USD
CY2021Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	10747000	USD
CY2021Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2879000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	5436000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	1395000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	4136000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2819000	USD
CY2021Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2512000	USD
CY2021Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3065000	USD
CY2020Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1254000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1143000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1928000	USD
CY2020Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	858000	USD
CY2021Q4	us-gaap	Net Income Loss NetIncomeLoss	8591000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	9198000	USD
CY2021Q2	us-gaap	Net Income Loss NetIncomeLoss	8235000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	9731000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	6084000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	4293000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	3323000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	3278000	USD
CY2021Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.01
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.07
CY2021Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.95
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.12
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.71
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.50
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.38
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.38
CY2021Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.01
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.07
CY2021Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.95
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.12
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.71
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.38
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.38
CY2021Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.18
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.18
CY2021Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.18
CY2021Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.18
CY2020Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.165
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.165
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.165
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.165
CY2021	dei	Auditor Name AuditorName	Crowe LLP
CY2021	dei	Auditor Location AuditorLocation	Oak Brook, Illinois
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	219837	shares

Files In Submission

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$FBIZ
FIRST BUSINESS FINANCIAL SERVICES, INC. Stock $fbiz

2021 Q4 Form 10-K Financial Statement

#000152195122000016 Filed on February 23, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FBIZ FIRST BUSINESS FINANCIAL SERVICES, INC. Stock $fbiz

2021 Q4 Form 10-K Financial Statement

#000152195122000016 Filed on February 23, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FBIZ
FIRST BUSINESS FINANCIAL SERVICES, INC. Stock $fbiz