XML 94 R82.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Regulatory Capital (Regulatory Capital Ratios) (Details) $ in Thousands | Sep. 30, 2022 USD ($) | Dec. 31, 2021 USD ($)
--- | --- | ---
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 317,840 | $ 281,745
Total capital to risk-weighted assets | 0.1166 | 0.1082
Total capital, Minimum Required for Capital Adequacy Purposes | $ 218,100 | $ 208,337
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0800 | 0.0800
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 286,257 | $ 273,443
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Tier 1 capital | $ 258,435 | $ 232,795
Tier 1 capital to risk-weighted assets | 0.0948 | 0.0894
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 163,575 | $ 156,253
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0600 | 0.0600
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 231,732 | $ 221,358
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Common equity tier 1 capital | $ 246,443 | $ 222,719
Common equity tier 1 capital to risk-weighted assets | 9.04% | 8.55%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 122,682 | $ 117,190
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 190,838 | $ 182,295
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Tier 1 leverage capital | $ 258,435 | $ 232,795
Tier 1 leverage capital to average assets | 0.0934 | 0.0894
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 110,684 | $ 104,145
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.0400 | 0.0400
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 110,684 | $ 104,145
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
First Business Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 313,112 | $ 280,448
Total capital to risk-weighted assets | 0.1149 | 0.1078
Total capital, Minimum Required for Capital Adequacy Purposes | $ 217,954 | $ 208,142
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0800 | 0.0800
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 286,065 | $ 273,187
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 272,443 | $ 260,178
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.1000 | 0.1000
Tier 1 capital | $ 288,014 | $ 255,286
Tier 1 capital to risk-weighted assets | 0.1057 | 0.0981
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 163,466 | $ 156,107
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0600 | 0.0600
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 231,576 | $ 221,151
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 217,954 | $ 208,142
Tier 1 capital to risk weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.0800 | 0.0800
Common equity tier 1 capital | $ 288,014 | $ 255,286
Common equity tier 1 capital to risk-weighted assets | 10.57% | 9.81%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 122,599 | $ 117,080
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 190,710 | $ 182,124
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 177,088 | $ 169,116
Common equity tier 1 capital to risk-weighted assets, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | 6.50% | 6.50%
Tier 1 leverage capital | $ 288,014 | $ 255,286
Tier 1 leverage capital to average assets | 0.1042 | 0.0981
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 110,602 | $ 104,045
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.0400 | 0.0400
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 110,602 | $ 104,045
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 138,253 | $ 130,056
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.0500 | 0.0500

X
- Definition Capital Required for Capital Adequacy Plus Capital Conservation Buffer + References No definition available. + Details
Name: | fbiz_CapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets + References No definition available. + Details
Name: | fbiz_CapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Equity Tier One Capital Required for Capital Adequacy to Risk-Weighted Assets + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitalRequiredforCapitalAdequacytoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Equity Tier One Capital Required to be Well Capitalized to Risk-Weighted Assets + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitalRequiredtobeWellCapitalizedtoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Equity Tier One Capital to Risk-Weighted Assets + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitaltoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Common Equity Tier One Capital to be Well Capitalized + References No definition available. + Details
Name: | fbiz_CommonEquityTierOneCapitaltobeWellCapitalized
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer + References No definition available. + Details
Name: | fbiz_TierOneLeverageCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets + References No definition available. + Details
Name: | fbiz_TierOneLeverageCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer + References No definition available. + Details
Name: | fbiz_TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusCapitalConservationBuffer
Namespace Prefix: | fbiz_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets + References No definition available. + Details
Name: | fbiz_TierOneRiskBasedCapitalRequiredforCapitalAdequacyPlusConservationBuffertoRiskWeightedAssets
Namespace Prefix: | fbiz_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of total capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_Capital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of minimum Common Equity Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of Tier 1 leverage capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of minimum Tier 1 leverage capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of Tier 1 capital to average assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of Tier 1 risk-based capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of minimum Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=fbiz_FirstBusinessBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |