XML 110 R96.htm IDEA: XBRL DOCUMENT v3.20.4

FHLB Advances, Other Borrowings and Junior Subordinated Notes (Composition of Borrowed Funds) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Apr. 28, 2020
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 429,229	$ 329,429
Borrowed Funds, Average Balance	$ 429,624	$ 321,740
Borrowed funds, interest rate during period	1.91%	2.87%
Federal funds purchased
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 0	$ 0
Borrowed Funds, Average Balance	$ 71	$ 59
Borrowed funds, interest rate during period	0.69%	2.45%
Federal Reserve PPPLF
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 0	$ 0	$ 29,600
Borrowed Funds, Average Balance	$ 15,207	$ 0
Borrowed funds, interest rate during period	0.35%	0.00%
FHLB advances
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 394,500	$ 295,000
Borrowed Funds, Average Balance	$ 379,891	$ 286,464
Borrowed funds, interest rate during period	1.45%	2.17%
Other borrowings
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 920	$ 675
Borrowed Funds, Average Balance	$ 676	$ 675
Borrowed funds, interest rate during period	12.60%	8.11%
Subordinated notes payable(1)
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 23,747	$ 23,707
Borrowed Funds, Average Balance	$ 23,725	$ 24,502
Borrowed funds, interest rate during period	5.95%	7.45%
Junior subordinated notes
Composition of Borrowed Funds [Line Items]
Junior subordinated notes and other borrowings	$ 10,062	$ 10,047
Borrowed Funds, Average Balance	$ 10,054	$ 10,040
Borrowed funds, interest rate during period	11.09%	11.08%

X

- Definition

Borrowed Funds, Average Balance

+ References

No definition available.

+ Details

Name:	fbiz_BorrowedFundsAverageBalance
Namespace Prefix:	fbiz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

[Line Items] for Composition of Borrowed Funds [Table]

+ References

No definition available.

+ Details

Name:	fbiz_CompositionofBorrowedFundsLineItems
Namespace Prefix:	fbiz_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of short-term and long-term debt and lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_FederalFundsPurchasedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=fbiz_FederalReservePaycheckProtectionProgramLendingFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=fbiz_FHLBadvancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=fbiz_OtherBorrowingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_SubordinatedDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: