XML 78 R60.htm IDEA: XBRL DOCUMENT
v3.21.2

Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Impaired Loans and Leases) (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020
Recorded Investment(1) |  |
With no impairment reserve recorded | $ 4,985 | $ 18,966
With impairment reserve recorded | 2,501 | 7,697
Total | 7,486 | 26,663
Unpaid Principal Balance |  |
With no impairment reserve recorded | 5,129 | 29,191
With impairment reserve recorded | 2,501 | 12,103
Total | 7,630 | 41,294
Impairment Reserve |  |
Impairment Reserve | 1,570 | 3,681
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 14,817 | 21,709
With impairment reserve recorded | 1,883 | 5,994
Total | 16,700 | 27,703
Foregone Interest Income |  |
With no impairment reserve recorded | 898 | 2,082
With impairment reserve recorded | 104 | 712
Foregone interest income | 1,002 | 2,794
Interest Income Recognized |  |
With no impairment reserve recorded | 156 | 636
With impairment reserve recorded | 8 | 0
Total | 164 | 636
Net Foregone Interest Income |  |
With no impairment reserve recorded | 742 | 1,446
With impairment reserve recorded | 96 | 712
Total | 838 | 2,158
Commercial real estate — owner occupied |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 1,109 | 4,338
With impairment reserve recorded | 0 | 1,091
Total | 1,109 | 5,429
Unpaid Principal Balance |  |
With no impairment reserve recorded | 1,147 | 4,365
With impairment reserve recorded | 0 | 4,792
Total | 1,147 | 9,157
Impairment Reserve |  |
Impairment Reserve | 0 | 471
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 2,771 | 4,565
With impairment reserve recorded | 0 | 2,349
Total | 2,771 | 6,914
Foregone Interest Income |  |
With no impairment reserve recorded | 135 | 291
With impairment reserve recorded | 0 | 384
Foregone interest income | 135 | 675
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 72
With impairment reserve recorded | 0 | 0
Total | 0 | 72
Net Foregone Interest Income |  |
With no impairment reserve recorded | 135 | 219
With impairment reserve recorded | 0 | 384
Total | 135 | 603
Commercial real estate — non-owner occupied |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 3,783
With impairment reserve recorded | 0 | 0
Total | 0 | 3,783
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 6,563
With impairment reserve recorded | 0 | 0
Total | 0 | 6,563
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 3,049 | 1,519
With impairment reserve recorded | 0 | 0
Total | 3,049 | 1,519
Foregone Interest Income |  |
With no impairment reserve recorded | 233 | 486
With impairment reserve recorded | 0 | 0
Foregone interest income | 233 | 486
Interest Income Recognized |  |
With no impairment reserve recorded | 16 | 0
With impairment reserve recorded | 0 | 0
Total | 16 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 217 | 486
With impairment reserve recorded | 0 | 0
Total | 217 | 486
Land development |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 890
With impairment reserve recorded | 0 | 0
Total | 0 | 890
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 5,187
With impairment reserve recorded | 0 | 0
Total | 0 | 5,187
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 10 | 1,192
With impairment reserve recorded | 0 | 0
Total | 10 | 1,192
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 14
With impairment reserve recorded | 0 | 0
Foregone interest income | 0 | 14
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 14
With impairment reserve recorded | 0 | 0
Total | 0 | 14
Construction |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Foregone interest income | 0 | 0
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Multi-family |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Foregone interest income | 0 | 0
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
1-4 family |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 391 | 46
With impairment reserve recorded | 0 | 250
Total | 391 | 296
Unpaid Principal Balance |  |
With no impairment reserve recorded | 396 | 51
With impairment reserve recorded | 0 | 250
Total | 396 | 301
Impairment Reserve |  |
Impairment Reserve | 0 | 29
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 261 | 307
With impairment reserve recorded | 0 | 21
Total | 261 | 328
Foregone Interest Income |  |
With no impairment reserve recorded | 55 | 31
With impairment reserve recorded | 0 | 0
Foregone interest income | 55 | 31
Interest Income Recognized |  |
With no impairment reserve recorded | 18 | 141
With impairment reserve recorded | 0 | 0
Total | 18 | 141
Net Foregone Interest Income |  |
With no impairment reserve recorded | 37 | (110)
With impairment reserve recorded | 0 | 0
Total | 37 | (110)
Commercial and industrial |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 3,485 | 9,888
With impairment reserve recorded | 2,452 | 6,267
Total | 5,937 | 16,155
Unpaid Principal Balance |  |
With no impairment reserve recorded | 3,586 | 12,337
With impairment reserve recorded | 2,452 | 6,972
Total | 6,038 | 19,309
Impairment Reserve |  |
Impairment Reserve | 1,521 | 3,125
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 8,662 | 13,951
With impairment reserve recorded | 1,834 | 3,585
Total | 10,496 | 17,536
Foregone Interest Income |  |
With no impairment reserve recorded | 445 | 1,219
With impairment reserve recorded | 102 | 324
Foregone interest income | 547 | 1,543
Interest Income Recognized |  |
With no impairment reserve recorded | 113 | 423
With impairment reserve recorded | 8 | 0
Total | 121 | 423
Net Foregone Interest Income |  |
With no impairment reserve recorded | 332 | 796
With impairment reserve recorded | 94 | 324
Total | 426 | 1,120
Direct financing leases, net |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 49 | 49
Total | 49 | 49
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 49 | 49
Total | 49 | 49
Impairment Reserve |  |
Impairment Reserve | 49 | 49
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 0 | 89
With impairment reserve recorded | 49 | 39
Total | 49 | 128
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 2 | 3
Foregone interest income | 2 | 3
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 2 | 3
Total | 2 | 3
Home equity and second mortgages |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 40
Total | 0 | 40
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 40
Total | 0 | 40
Impairment Reserve |  |
Impairment Reserve | 0 | 7
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 53 | 1
With impairment reserve recorded | 0 | 0
Total | 53 | 1
Foregone Interest Income |  |
With no impairment reserve recorded | 7 | 0
With impairment reserve recorded | 0 | 1
Foregone interest income | 7 | 1
Interest Income Recognized |  |
With no impairment reserve recorded | 9 | 0
With impairment reserve recorded | 0 | 0
Total | 9 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | (2) | 0
With impairment reserve recorded | 0 | 1
Total | (2) | 1
Other |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 21
With impairment reserve recorded | 0 | 0
Total | 0 | 21
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 688
With impairment reserve recorded | 0 | 0
Total | 0 | 688
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 11 | 85
With impairment reserve recorded | 0 | 0
Total | 11 | 85
Foregone Interest Income |  |
With no impairment reserve recorded | 23 | 41
With impairment reserve recorded | 0 | 0
Foregone interest income | 23 | 41
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 0 | 0
Total | 0 | 0
Net Foregone Interest Income |  |
With no impairment reserve recorded | 23 | 41
With impairment reserve recorded | 0 | 0
Total | $ 23 | $ 41

X
- Definition Foregone interest income [Abstract] + References No definition available. + Details
Name: | fbiz_ForegoneInterestIncomeAbstract
Namespace Prefix: | fbiz_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Impaired Financing Receivable, Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impaired Financing Receivable, Net Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableNetForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impaired Financing Receivable, with No Related Allowance, Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableWithNoRelatedAllowanceForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impaired Financing Receivable, with No Related Allowance, Net Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableWithNoRelatedAllowanceNetForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impaired Financing Receivable, with Related Allowance, Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableWithRelatedAllowanceForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impaired Financing Receivable, with Related Allowance, Net Foregone Interest Income + References No definition available. + Details
Name: | fbiz_ImpairedFinancingReceivableWithRelatedAllowanceNetForegoneInterestIncome
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impairment reserve [Abstract] + References No definition available. + Details
Name: | fbiz_ImpairmentReserveAbstract
Namespace Prefix: | fbiz_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net foregone interest income [Abstract] + References No definition available. + Details
Name: | fbiz_NetForegoneInterestIncomeAbstract
Namespace Prefix: | fbiz_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income on financing receivables, for which there is a related allowance for credit losses, recognized on a cash-basis method of accounting that the financing receivables were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeCashBasisMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_CommercialRealEstateLoansReceivableLandDevelopmentMember
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_CommercialAndIndustrialLoansReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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