XML 67 R58.htm IDEA: XBRL DOCUMENT
v3.23.1

Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Summary of Activity in Allowance for Loan and Lease Losses) (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2022
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - begin | $ 24,230,000 |  |
Charge-offs | (166,000) |  |
Net (charge-offs) recoveries | (59,000) |  |
Allowance for loan and lease losses - end | 26,140,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 1,410,000 |  | $ 0
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 24,230,000 | $ 24,336,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff |  | 22,000 |
Financing Receivable, Allowance for Credit Loss, Recovery | 107,000 | 210,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  | 188,000 |
Financing Receivable, Credit Loss, Expense (Reversal) | 1,561,000 | (855,000) |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 26,140,000 | 23,669,000 |
Financing Receivable, Allowance for Credit Loss, Including | 27,550,000 |  | 24,230,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 24,518,000 |  | 22,580,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 1,622,000 |  | 1,650,000
Financing Receivable, Collectively Evaluated for Impairment | 2,535,864,000 |  | 2,439,400,000
Financing Receivable, Individually Evaluated for Impairment | 3,412,000 |  | 3,815,000
Loans and Leases Receivable, Gross | 2,539,276,000 |  | 2,443,215,000
Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Off-Balance-Sheet, Credit Loss, Liability |  |  | 1,334,000
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 484,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 1,818,000 |  |
Commercial real estate — owner occupied |  |  |
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - end | 1,636,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 20,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 1,766,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 |  |
Financing Receivable, Allowance for Credit Loss, Recovery | 0 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery | 0 |  |
Financing Receivable, Credit Loss, Expense (Reversal) | 94,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 1,636,000 |  |
Financing Receivable, Allowance for Credit Loss, Including | 1,656,000 |  | 1,766,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 1,636,000 |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  |
Financing Receivable, Collectively Evaluated for Impairment | 233,725,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 |  |
Loans and Leases Receivable, Gross | 233,725,000 |  |
Commercial real estate — owner occupied | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | (218,000) |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | (204,000) |  |
Commercial real estate — non-owner occupied |  |  |
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - end | 4,915,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 51,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 5,108,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 |  |
Financing Receivable, Allowance for Credit Loss, Recovery | 1,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery | 1,000 |  |
Financing Receivable, Credit Loss, Expense (Reversal) | 99,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 4,915,000 |  |
Financing Receivable, Allowance for Credit Loss, Including | 4,966,000 |  | 5,108,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 4,915,000 |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  |
Financing Receivable, Collectively Evaluated for Impairment | 675,087,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 |  |
Loans and Leases Receivable, Gross | 675,087,000 |  |
Commercial real estate — non-owner occupied | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | (297,000) |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | (242,000) |  |
Construction |  |  |
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - end | 1,586,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 701,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 1,646,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 |  |
Financing Receivable, Allowance for Credit Loss, Recovery | 0 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery | 0 |  |
Financing Receivable, Credit Loss, Expense (Reversal) | (155,000) |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 1,586,000 |  |
Financing Receivable, Allowance for Credit Loss, Including | 2,287,000 |  | 1,646,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 1,586,000 |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  |
Financing Receivable, Collectively Evaluated for Impairment | 212,916,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 |  |
Loans and Leases Receivable, Gross | 212,916,000 |  |
Construction | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 109,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 796,000 |  |
Multi-family |  |  |
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - end | 2,892,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 9,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 2,634,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 |  |
Financing Receivable, Allowance for Credit Loss, Recovery | 0 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery | 0 |  |
Financing Receivable, Credit Loss, Expense (Reversal) | 653,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 2,892,000 |  |
Financing Receivable, Allowance for Credit Loss, Including | 2,901,000 |  | 2,634,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 2,892,000 |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  |
Financing Receivable, Collectively Evaluated for Impairment | 384,043,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 0 |  |
Loans and Leases Receivable, Gross | 384,043,000 |  |
Multi-family | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | (391,000) |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | (386,000) |  |
1-4 family |  |  |
Allowance for credit losses roll-forward |  |  |
Allowance for loan and lease losses - end | 201,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 20,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 207,000 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 |  |
Financing Receivable, Allowance for Credit Loss, Recovery | 0 |  |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery | 0 |  |
Financing Receivable, Credit Loss, Expense (Reversal) | 59,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 201,000 |  |
Financing Receivable, Allowance for Credit Loss, Including | 221,000 |  | 207,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 201,000 |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  |
Financing Receivable, Collectively Evaluated for Impairment | 23,376,000 |  |
Financing Receivable, Individually Evaluated for Impairment | 28,000 |  |
Loans and Leases Receivable, Gross | 23,404,000 |  |
1-4 family | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | (60,000) |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | (45,000) |  |
Commercial and industrial |  |  |
Allowance for credit losses roll-forward |  |  |
Charge-offs | (166,000) |  |
Net (charge-offs) recoveries | (71,000) |  |
Allowance for loan and lease losses - end | 14,348,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 557,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 12,403,000 | 8,413,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff |  | 22,000 |
Financing Receivable, Allowance for Credit Loss, Recovery | 95,000 | 84,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  | 62,000 |
Financing Receivable, Credit Loss, Expense (Reversal) | 700,000 | 437,000 |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 14,348,000 | 8,912,000 |
Financing Receivable, Allowance for Credit Loss, Including | 14,905,000 |  | 12,403,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment | 12,726,000 |  | 10,753,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 1,622,000 |  | 1,650,000
Financing Receivable, Collectively Evaluated for Impairment | 959,944,000 |  | 849,542,000
Financing Receivable, Individually Evaluated for Impairment | 3,384,000 |  | 3,785,000
Loans and Leases Receivable, Gross | 963,328,000 |  | 853,327,000
Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 1,359,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 1,873,000 |  |
Total consumer and other |  |  |
Allowance for credit losses roll-forward |  |  |
Charge-offs | 0 |  |
Net (charge-offs) recoveries | 11,000 |  |
Allowance for loan and lease losses - end | 562,000 |  |
Off-Balance-Sheet, Credit Loss, Liability | 52,000 |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | 466,000 | 813,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff |  | 0 |
Financing Receivable, Allowance for Credit Loss, Recovery | 11,000 | 10,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  | 10,000 |
Financing Receivable, Credit Loss, Expense (Reversal) | 111,000 | 169,000 |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance |  | 992,000 |
Financing Receivable, Allowance for Credit Loss, Including | 614,000 |  | 466,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment |  |  | 466,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment |  |  | 0
Financing Receivable, Collectively Evaluated for Impairment |  |  | 47,938,000
Financing Receivable, Individually Evaluated for Impairment |  |  | 0
Loans and Leases Receivable, Gross |  |  | 47,938,000
Total consumer and other | Cumulative Effect, Period of Adoption, Adjustment |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance | 26,000 |  |
Total commercial real estate |  |  |
Allowance for credit losses roll-forward |  |  |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance | $ 11,361,000 | 15,110,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff |  | 0 |
Financing Receivable, Allowance for Credit Loss, Recovery |  | 116,000 |
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  | 116,000 |
Financing Receivable, Credit Loss, Expense (Reversal) |  | (1,461,000) |
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance |  | $ 13,765,000 |
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment |  |  | 11,361,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment |  |  | 0
Financing Receivable, Collectively Evaluated for Impairment |  |  | 1,541,920,000
Financing Receivable, Individually Evaluated for Impairment |  |  | 30,000
Loans and Leases Receivable, Gross |  |  | $ 1,541,950,000

X
- Definition Financing Receivable, Allowance for Credit Loss, Including unfunded credit commitment reserves + References No definition available. + Details
Name: | fbiz_FinancingReceivableAllowanceForCreditLossIncluding
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after recoveries, of loans and leases that have been written-off. + References No definition available. + Details
Name: | us-gaap_AllowanceForLoanAndLeaseLossesWriteoffsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (4) + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (e) -URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (d) -URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The balance of financing receivables that were individually evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI https://asc.fasb.org/extlink&oid=122038336&loc=d3e74567-122707 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI https://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=121611286&loc=d3e11927-110247 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 2 -URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82919202-210446 + Details
Name: | us-gaap_OffBalanceSheetCreditLossLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of credit loss expense (reversal of expense) for financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(11)) -URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 + Details
Name: | us-gaap_ProvisionForLoanLossesExpensed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fbiz_CommercialRealEstateLoansReceivable14FamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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