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Employee Benefit Plans (Bank Owned Life Insurance) (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
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Bank owned life insurance [Line Items] |  |
Bank-owned life insurance | $ 55,536 | $ 54,018
Bank owned life insurance death benefits | 133,700 | 133,800
Insured executive officers with deferred compensation plans |  |
Bank owned life insurance [Line Items] |  |
Bank-owned life insurance | 3,100 | 2,900
Bank owned life insurance death benefits | 6,200 | 6,100
Other insured individuals |  |
Bank owned life insurance [Line Items] |  |
Bank-owned life insurance | $ 52,400 | $ 51,000

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- Definition Bank Owned Life Insurance Death Benefits + References No definition available. + Details
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Namespace Prefix: | fbiz_
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- Definition [Line Items] for Bank owned life insurance [Table] + References No definition available. + Details
Name: | fbiz_BankOwnedLifeInsuranceLineItems
Namespace Prefix: | fbiz_
Data Type: | xbrli:stringItemType
Balance Type: | na
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- Definition The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
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Balance Type: | debit
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- Details
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- Details
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