XML 71 R61.htm IDEA: XBRL DOCUMENT
v3.20.2

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, 2020 | Dec. 31, 2019
Recorded Investment(1) |  |
With no impairment reserve recorded | $ 15,557 | $ 7,312
With impairment reserve recorded | 20,540 | 13,441
Total | 36,097 | 20,753
Unpaid Principal Balance |  |
With no impairment reserve recorded | 23,065 | 14,050
With impairment reserve recorded | 23,221 | 16,183
Total | 46,286 | 30,233
Impairment Reserve |  |
Impairment Reserve | 8,898 | 3,365
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 15,564 | 20,212
With impairment reserve recorded | 9,335 | 3,878
Total | 24,899 | 24,090
Foregone Interest Income |  |
With no impairment reserve recorded | 1,043 | 1,257
With impairment reserve recorded | 1,006 | 1,436
Foregone interest income | 2,049 | 2,693
Interest Income Recognized |  |
With no impairment reserve recorded | 467 | 793
With impairment reserve recorded | 0 | 0
Total | 467 | 793
Net Foregone Interest Income |  |
With no impairment reserve recorded | 576 | 464
With impairment reserve recorded | 1,006 | 1,436
Total | 1,582 | 1,900
Commercial real estate — owner occupied |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 4,471 | 387
With impairment reserve recorded | 3,470 | 3,645
Total | 7,941 | 4,032
Unpaid Principal Balance |  |
With no impairment reserve recorded | 4,498 | 387
With impairment reserve recorded | 4,829 | 5,004
Total | 9,327 | 5,391
Impairment Reserve |  |
Impairment Reserve | 2,974 | 1,082
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 3,092 | 3,285
With impairment reserve recorded | 3,534 | 1,511
Total | 6,626 | 4,796
Foregone Interest Income |  |
With no impairment reserve recorded | 149 | 64
With impairment reserve recorded | 297 | 414
Foregone interest income | 446 | 478
Interest Income Recognized |  |
With no impairment reserve recorded | 72 | 355
With impairment reserve recorded | 0 | 0
Total | 72 | 355
Net Foregone Interest Income |  |
With no impairment reserve recorded | 77 | (291)
With impairment reserve recorded | 297 | 414
Total | 374 | 123
Commercial real estate — non-owner occupied |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 5,813 | 0
Total | 5,813 | 0
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 5,813 | 0
Total | 5,813 | 0
Impairment Reserve |  |
Impairment Reserve | 2,768 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 35 | 58
With impairment reserve recorded | 21 | 0
Total | 56 | 58
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 1
With impairment reserve recorded | 399 | 0
Foregone interest income | 399 | 1
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 | 1
With impairment reserve recorded | 399 | 0
Total | 399 | 1
Land development |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 890 | 1,526
With impairment reserve recorded | 0 | 0
Total | 890 | 1,526
Unpaid Principal Balance |  |
With no impairment reserve recorded | 5,187 | 5,823
With impairment reserve recorded | 0 | 0
Total | 5,187 | 5,823
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 1,295 | 1,843
With impairment reserve recorded | 0 | 0
Total | 1,295 | 1,843
Foregone Interest Income |  |
With no impairment reserve recorded | 19 | 52
With impairment reserve recorded | 0 | 0
Foregone interest income | 19 | 52
Interest Income Recognized |  |
With no impairment reserve recorded | 0 | 6
With impairment reserve recorded | 0 | 0
Total | 0 | 6
Net Foregone Interest Income |  |
With no impairment reserve recorded | 19 | 46
With impairment reserve recorded | 0 | 0
Total | 19 | 46
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 | 380 | 473
With impairment reserve recorded | 0 | 0
Total | 380 | 473
Unpaid Principal Balance |  |
With no impairment reserve recorded | 385 | 478
With impairment reserve recorded | 0 | 0
Total | 385 | 478
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 416 | 356
With impairment reserve recorded | 0 | 0
Total | 416 | 356
Foregone Interest Income |  |
With no impairment reserve recorded | 30 | 19
With impairment reserve recorded | 0 | 0
Foregone interest income | 30 | 19
Interest Income Recognized |  |
With no impairment reserve recorded | 79 | 46
With impairment reserve recorded | 0 | 0
Total | 79 | 46
Net Foregone Interest Income |  |
With no impairment reserve recorded | (49) | (27)
With impairment reserve recorded | 0 | 0
Total | (49) | (27)
Commercial and industrial |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 9,787 | 4,779
With impairment reserve recorded | 10,906 | 9,796
Total | 20,693 | 14,575
Unpaid Principal Balance |  |
With no impairment reserve recorded | 12,300 | 6,549
With impairment reserve recorded | 12,228 | 11,179
Total | 24,528 | 17,728
Impairment Reserve |  |
Impairment Reserve | 2,981 | 2,283
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 10,620 | 14,479
With impairment reserve recorded | 5,724 | 2,367
Total | 16,344 | 16,846
Foregone Interest Income |  |
With no impairment reserve recorded | 813 | 1,073
With impairment reserve recorded | 308 | 1,022
Foregone interest income | 1,121 | 2,095
Interest Income Recognized |  |
With no impairment reserve recorded | 316 | 379
With impairment reserve recorded | 0 | 0
Total | 316 | 379
Net Foregone Interest Income |  |
With no impairment reserve recorded | 497 | 694
With impairment reserve recorded | 308 | 1,022
Total | 805 | 1,716
Direct financing leases, net |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 351 | 0
Total | 351 | 0
Unpaid Principal Balance |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 351 | 0
Total | 351 | 0
Impairment Reserve |  |
Impairment Reserve | 175 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 56 | 0
Total | 56 | 0
Foregone Interest Income |  |
With no impairment reserve recorded | 0 | 0
With impairment reserve recorded | 2 | 0
Foregone interest income | 2 | 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 | 2 | 0
Total | 2 | 0
Home equity and second mortgages |  |
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 | 7
With impairment reserve recorded | 0 | 0
Total | 0 | 7
Net Foregone Interest Income |  |
With no impairment reserve recorded | 0 | (7)
With impairment reserve recorded | 0 | 0
Total | 0 | (7)
Other |  |
Recorded Investment(1) |  |
With no impairment reserve recorded | 29 | 147
With impairment reserve recorded | 0 | 0
Total | 29 | 147
Unpaid Principal Balance |  |
With no impairment reserve recorded | 695 | 813
With impairment reserve recorded | 0 | 0
Total | 695 | 813
Impairment Reserve |  |
Impairment Reserve | 0 | 0
Average Recorded Investment(2) |  |
With no impairment reserve recorded | 106 | 191
With impairment reserve recorded | 0 | 0
Total | 106 | 191
Foregone Interest Income |  |
With no impairment reserve recorded | 32 | 48
With impairment reserve recorded | 0 | 0
Foregone interest income | 32 | 48
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 | 32 | 48
With impairment reserve recorded | 0 | 0
Total | $ 32 | $ 48

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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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=121611835&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: |