XML 66 R57.htm IDEA: XBRL DOCUMENT
v3.22.1

Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Impaired Loans and Leases) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Mar. 31, 2022 | Jun. 30, 2021 | Dec. 31, 2021
Recorded Investment(1) |  |  |
With no impairment reserve recorded | $ 4,284 |  | $ 4,419
With impairment reserve recorded | 1,536 |  | 2,156
Total | 5,820 |  | 6,575
Unpaid Principal Balance |  |  |
With no impairment reserve recorded | 4,427 |  | 4,564
With impairment reserve recorded | 1,536 |  | 2,156
Total | 5,963 |  | 6,720
Impairment Reserve |  |  |
Impairment Reserve | 1,225 |  | 1,505
Average Recorded Investment(2) |  |  |
With no impairment reserve recorded | 5,243 | $ 12,754 |
With impairment reserve recorded | 1,157 | 1,506 |
Total | 6,400 | 14,260 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 79 | 991 |
With impairment reserve recorded | 26 | 113 |
Foregone interest income | 105 | 1,104 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 28 | 446 |
With impairment reserve recorded | 0 | 8 |
Total | 28 | 454 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | 51 | 545 |
With impairment reserve recorded | 26 | 105 |
Total | 77 | 650 |
Commercial real estate — owner occupied |  |  |
Recorded Investment(1) |  |  |
With no impairment reserve recorded | 344 |  | 348
With impairment reserve recorded | 0 |  | 0
Total | 344 |  | 348
Unpaid Principal Balance |  |  |
With no impairment reserve recorded | 382 |  | 386
With impairment reserve recorded | 0 |  | 0
Total | 382 |  | 386
Impairment Reserve |  |  |
Impairment Reserve | 0 |  | 0
Average Recorded Investment(2) |  |  |
With no impairment reserve recorded | 346 | 2,217 |
With impairment reserve recorded | 0 | 0 |
Total | 346 | 2,217 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 6 | 145 |
With impairment reserve recorded | 0 | 0 |
Foregone interest income | 6 | 145 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 0 | 218 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 218 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | 6 | (73) |
With impairment reserve recorded | 0 | 0 |
Total | 6 | (73) |
Commercial real estate — non-owner occupied |  |  |
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 | 2,281 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 2,281 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | 233 |
With impairment reserve recorded | 0 | 0 |
Foregone interest income | 0 | 233 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 0 | 16 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 16 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | 217 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 217 |
Land development |  |  |
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 | 7 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 7 |
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 |
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 | 331 |  | 339
With impairment reserve recorded | 0 |  | 0
Total | 331 |  | 339
Unpaid Principal Balance |  |  |
With no impairment reserve recorded | 336 |  | 344
With impairment reserve recorded | 0 |  | 0
Total | 336 |  | 344
Impairment Reserve |  |  |
Impairment Reserve | 0 |  | 0
Average Recorded Investment(2) |  |  |
With no impairment reserve recorded | 335 | 285 |
With impairment reserve recorded | 0 | 0 |
Total | 335 | 285 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 5 | 60 |
With impairment reserve recorded | 0 | 0 |
Foregone interest income | 5 | 60 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 6 | 24 |
With impairment reserve recorded | 0 | 0 |
Total | 6 | 24 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | (1) | 36 |
With impairment reserve recorded | 0 | 0 |
Total | (1) | 36 |
Commercial and industrial |  |  |
Recorded Investment(1) |  |  |
With no impairment reserve recorded | 3,609 |  | 3,717
With impairment reserve recorded | 1,452 |  | 2,072
Total | 5,061 |  | 5,789
Unpaid Principal Balance |  |  |
With no impairment reserve recorded | 3,709 |  | 3,819
With impairment reserve recorded | 1,452 |  | 2,072
Total | 5,161 |  | 5,891
Impairment Reserve |  |  |
Impairment Reserve | 1,141 |  | 1,439
Average Recorded Investment(2) |  |  |
With no impairment reserve recorded | 4,546 | 7,914 |
With impairment reserve recorded | 1,084 | 1,456 |
Total | 5,630 | 9,370 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 68 | 522 |
With impairment reserve recorded | 25 | 109 |
Foregone interest income | 93 | 631 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 21 | 179 |
With impairment reserve recorded | 0 | 8 |
Total | 21 | 187 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | 47 | 343 |
With impairment reserve recorded | 25 | 101 |
Total | 72 | 444 |
Direct financing leases, net |  |  |
Recorded Investment(1) |  |  |
With no impairment reserve recorded | 0 |  | 15
With impairment reserve recorded | 84 |  | 84
Total | 84 |  | 99
Unpaid Principal Balance |  |  |
With no impairment reserve recorded | 0 |  | 15
With impairment reserve recorded | 84 |  | 84
Total | 84 |  | 99
Impairment Reserve |  |  |
Impairment Reserve | 84 |  | 66
Average Recorded Investment(2) |  |  |
With no impairment reserve recorded | 16 | 2 |
With impairment reserve recorded | 73 | 50 |
Total | 89 | 52 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | 1 |
With impairment reserve recorded | 1 | 4 |
Foregone interest income | 1 | 5 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 1 | 0 |
With impairment reserve recorded | 0 | 0 |
Total | 1 | 0 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | (1) | 1 |
With impairment reserve recorded | 1 | 4 |
Total | 0 | 5 |
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 | 40 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 40 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | 7 |
With impairment reserve recorded | 0 | 0 |
Foregone interest income | 0 | 7 |
Interest Income Recognized |  |  |
With no impairment reserve recorded | 0 | 9 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 9 |
Net Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | (2) |
With impairment reserve recorded | 0 | 0 |
Total | 0 | (2) |
Other |  |  |
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 | 8 |
With impairment reserve recorded | 0 | 0 |
Total | 0 | 8 |
Foregone Interest Income |  |  |
With no impairment reserve recorded | 0 | 23 |
With impairment reserve recorded | 0 | 0 |
Foregone interest income | 0 | 23 |
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 | 23 |
With impairment reserve recorded | 0 | 0 |
Total | $ 0 | $ 23 |

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: |