XML 70 R61.htm IDEA: XBRL DOCUMENT
v3.22.2

Other Real Estate Owned and Repossessed Assets - Summary of Repossessed Assets Activity (Details) - USD ($) $ in Thousands | 6 Months Ended
--- | ---
Jun. 30, 2022 | Jun. 30, 2021
Other Real Estate And Other Assets Acquired In Foreclosure [Line Items] |  |
Sales proceeds | $ (2,206) | $ (142)
Gross gains | 361 | 56
Gross losses | (27) |
Net gains (losses) | 334 | 56
Impairment | (1) | (17)
Repossessed Assets [Member] |  |
Other Real Estate And Other Assets Acquired In Foreclosure [Line Items] |  |
Beginning balance | 154 | 245
Transfers from loans | 329 | 515
Sales proceeds | (151) | (588)
Gross losses | (131) | (67)
Net gains (losses) | (131) | (67)
Ending balance | $ 201 | $ 105

X
- Definition Other real estate and other assets acquired in foreclosure. + References No definition available. + Details
Name: | fusb_OtherRealEstateAndOtherAssetsAcquiredInForeclosureLineItems
Namespace Prefix: | fusb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Other real estate gross gains. + References No definition available. + Details
Name: | fusb_OtherRealEstateGrossGains
Namespace Prefix: | fusb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other real estate gross losses. + References No definition available. + Details
Name: | fusb_OtherRealEstateGrossLosses
Namespace Prefix: | fusb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Other real estate net income loss. + References No definition available. + Details
Name: | fusb_OtherRealEstateNetIncomeLoss
Namespace Prefix: | fusb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Real estate owned, transfer to loan. + References No definition available. + Details
Name: | fusb_RealEstateOwnedTransferToLoan
Namespace Prefix: | fusb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The charge against earnings in the period to reduce the carrying amount of real property to fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 + Details
Name: | us-gaap_ImpairmentOfRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of assets other than real property that were received in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11 -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5162-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 3 -URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4437-111522 + Details
Name: | us-gaap_OtherForeclosedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash inflow associated with the sale of other real estate not otherwise defined in the taxonomy. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfOtherRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=fusb_RepossessedAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |