XML 12 R54.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Impaired Loans and Leases) (Details) - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2015 | Dec. 31, 2014
Recorded investment |  |  |  |
With no impairment reserve recorded | $ 14,876 |  | $ 11,270 |
With impairment reserve recorded | 2,266 |  | 525 |
Total | 17,142 |  | 11,795 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 18,660 |  | 15,623 |
With impairment reserve recorded | 2,312 |  | 565 |
Total | 20,972 |  | 16,188 |
Impairment reserve |  |  |  |
Impairment reserve | 575 |  | 290 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 9,350 | [1] | 13,926 | [2]
With impairment reserve recorded | 1,808 | [1] | 548 | [2]
Total | 11,158 | [1] | 14,474 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 259 |  | 843 |
With impairment reserve recorded | 58 |  | 27 |
Foregone interest income | 317 |  | 870 |
Interest income recognized |  |  |  |
With no impairment reserve recorded | 1 |  | 740 |
With impairment reserve recorded | 0 |  | 0 |
Total | 1 |  | 740 |
Net foregone interest income |  |  |  |
With no impairment reserve recorded | 258 |  | 103 |
With impairment reserve recorded | 58 |  | 27 |
Total | 316 |  | 130 |
Commercial real estate — owner occupied |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 564 |  | 577 |
With impairment reserve recorded | 89 |  | 0 |
Total | 653 |  | 577 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 564 |  | 577 |
With impairment reserve recorded | 89 |  | 0 |
Total | 653 |  | 577 |
Impairment reserve |  |  |  |
Impairment reserve | 4 |  | 0 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 575 | [1] | 484 | [2]
With impairment reserve recorded | 17 | [1] | 0 | [2]
Total | 592 | [1] | 484 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 13 |  | 30 |
With impairment reserve recorded | 0 |  | 0 |
Foregone interest income | 13 |  | 30 |
Interest income recognized |  |  |  |
With no impairment reserve recorded | 0 |  | 79 |
With impairment reserve recorded | 0 |  | 0 |
Total | 0 |  | 79 |
Net foregone interest income |  |  |  |
With no impairment reserve recorded | 13 |  | (49) |
With impairment reserve recorded | 0 |  | 0 |
Total | 13 |  | (49) |
Commercial real estate — non-owner occupied |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 860 |  | 921 |
With impairment reserve recorded | 47 |  | 49 |
Total | 907 |  | 970 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 860 |  | 921 |
With impairment reserve recorded | 87 |  | 89 |
Total | 947 |  | 1,010 |
Impairment reserve |  |  |  |
Impairment reserve | 47 |  | 49 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 918 | [1] | 349 | [2]
With impairment reserve recorded | 48 | [1] | 52 | [2]
Total | 966 | [1] | 401 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 6 |  | 22 |
With impairment reserve recorded | 2 |  | 4 |
Foregone interest income | 8 |  | 26 |
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 | 6 |  | 22 |
With impairment reserve recorded | 2 |  | 4 |
Total | 8 |  | 26 |
Construction and land development |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 4,617 |  | 5,157 |
With impairment reserve recorded | 0 |  | 0 |
Total | 4,617 |  | 5,157 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 7,287 |  | 7,828 |
With impairment reserve recorded | 0 |  | 0 |
Total | 7,287 |  | 7,828 |
Impairment reserve |  |  |  |
Impairment reserve | 0 |  | 0 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 5,039 | [1] | 5,285 | [2]
With impairment reserve recorded | 0 | [1] | 0 | [2]
Total | 5,039 | [1] | 5,285 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 71 |  | 155 |
With impairment reserve recorded | 0 |  | 0 |
Foregone interest income | 71 |  | 155 |
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 | 71 |  | 155 |
With impairment reserve recorded | 0 |  | 0 |
Total | 71 |  | 155 |
Multi-family |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 10 |  | 17 |
With impairment reserve recorded | 0 |  | 0 |
Total | 10 |  | 17 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 377 |  | 384 |
With impairment reserve recorded | 0 |  | 0 |
Total | 377 |  | 384 |
Impairment reserve |  |  |  |
Impairment reserve | 0 |  | 0 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 13 | [1] | 24 | [2]
With impairment reserve recorded | 0 | [1] | 0 | [2]
Total | 13 | [1] | 24 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 24 |  | 53 |
With impairment reserve recorded | 0 |  | 0 |
Foregone interest income | 24 |  | 53 |
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 | 24 |  | 53 |
With impairment reserve recorded | 0 |  | 0 |
Total | 24 |  | 53 |
1-4 family |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 1,442 |  | 1,181 |
With impairment reserve recorded | 918 |  | 390 |
Total | 2,360 |  | 1,571 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 1,514 |  | 1,218 |
With impairment reserve recorded | 924 |  | 390 |
Total | 2,438 |  | 1,608 |
Impairment reserve |  |  |  |
Impairment reserve | 177 |  | 155 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 1,578 | [1] | 380 | [2]
With impairment reserve recorded | 375 | [1] | 405 | [2]
Total | 1,953 | [1] | 785 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 33 |  | 15 |
With impairment reserve recorded | 11 |  | 18 |
Foregone interest income | 44 |  | 33 |
Interest income recognized |  |  |  |
With no impairment reserve recorded | 0 |  | 12 |
With impairment reserve recorded | 0 |  | 0 |
Total | 0 |  | 12 |
Net foregone interest income |  |  |  |
With no impairment reserve recorded | 33 |  | 3 |
With impairment reserve recorded | 11 |  | 18 |
Total | 44 |  | 21 |
Commercial and industrial |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 6,375 |  | 2,316 |
With impairment reserve recorded | 1,031 |  | 33 |
Total | 7,406 |  | 2,349 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 6,384 |  | 2,926 |
With impairment reserve recorded | 1,031 |  | 33 |
Total | 7,415 |  | 2,959 |
Impairment reserve |  |  |  |
Impairment reserve | 253 |  | 33 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 231 | [1] | 6,141 | [2]
With impairment reserve recorded | 1,241 | [1] | 34 | [2]
Total | 1,472 | [1] | 6,175 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 63 |  | 463 |
With impairment reserve recorded | 38 |  | 0 |
Foregone interest income | 101 |  | 463 |
Interest income recognized |  |  |  |
With no impairment reserve recorded | 1 |  | 649 |
With impairment reserve recorded | 0 |  | 0 |
Total | 1 |  | 649 |
Net foregone interest income |  |  |  |
With no impairment reserve recorded | 62 |  | (186) |
With impairment reserve recorded | 38 |  | 0 |
Total | 100 |  | (186) |
Direct financing leases, net |  |  |  |
Recorded investment |  |  |  |
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(1) |  |  |  |
With no impairment reserve recorded | 0 | [1] | 0 | [2]
With impairment reserve recorded | 0 | [1] | 0 | [2]
Total | 0 | [1] | 0 | [2]
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 |
Home equity and second mortgages |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 317 |  | 380 |
With impairment reserve recorded | 181 |  | 53 |
Total | 498 |  | 433 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 317 |  | 380 |
With impairment reserve recorded | 181 |  | 53 |
Total | 498 |  | 433 |
Impairment reserve |  |  |  |
Impairment reserve | 94 |  | 53 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 292 | [1] | 495 | [2]
With impairment reserve recorded | 127 | [1] | 57 | [2]
Total | 419 | [1] | 552 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 8 |  | 18 |
With impairment reserve recorded | 7 |  | 5 |
Foregone interest income | 15 |  | 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 | 8 |  | 18 |
With impairment reserve recorded | 7 |  | 5 |
Total | 15 |  | 23 |
Other |  |  |  |
Recorded investment |  |  |  |
With no impairment reserve recorded | 691 |  | 721 |
With impairment reserve recorded | 0 |  | 0 |
Total | 691 |  | 721 |
Unpaid principal balance |  |  |  |
With no impairment reserve recorded | 1,357 |  | 1,389 |
With impairment reserve recorded | 0 |  | 0 |
Total | 1,357 |  | 1,389 |
Impairment reserve |  |  |  |
Impairment reserve | 0 |  | 0 |
Average recorded investment(1) |  |  |  |
With no impairment reserve recorded | 704 | [1] | 768 | [2]
With impairment reserve recorded | 0 | [1] | 0 | [2]
Total | 704 | [1] | 768 | [2]
Foregone interest income |  |  |  |
With no impairment reserve recorded | 41 |  | 87 |
With impairment reserve recorded | 0 |  | 0 |
Foregone interest income | 41 |  | 87 |
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 | 41 |  | 87 |
With impairment reserve recorded | 0 |  | 0 |
Total | $ 41 |  | $ 87 |
[1] | (1)Average recorded investment is calculated primarily using daily average balances.
[2] | (1)Average recorded investment is calculated primarily using daily average balances.

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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5258-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35738203&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=35738203&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_CommercialRealEstateLoansReceivableConstructionAndLandDevelopmentMember
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_FinanceLeasesFinancingReceivableMember
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: |