v3.26.3
Commitments and Contingencies - Additional Information (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
SBA loans, probability of future losses
$ 0
$ 502,000
X
- Definition
SBA Loans, Probability of Future Losses
+ References
No definition available.
+ Details
Name:
fbiz_SBALoansProbabilityofFutureLosses
Namespace Prefix:
fbiz_
Data Type:
xbrli:monetaryItemType
Balance Type:
debit
Period Type:
instant
X
- References
No definition available.
+ Details
Name:
us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration