Name:	ucba_FinancingReceivableModificationsAverageRecordedInvestments
Namespace Prefix:	ucba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of allowance for credit losses related to recorded investment related to financing receivables that have been modified by troubled debt restructurings.

No definition available.

Name:	ucba_FinancingReceivableModificationsRelatedAllowance
Namespace Prefix:	ucba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of the unpaid principal balance in financing receivables as of the balance sheet date that have been modified by troubled debt restructurings.

No definition available.

Name:	ucba_FinancingReceivableModificationsUnpaidPrincipalBalance
Namespace Prefix:	ucba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of the unpaid principal balance in financing receivables that are on accrual status as of the balance sheet date that have been modified by troubled debt restructurings

No definition available.

Name:	ucba_FinancingReceivableModificationsUnpaidPrincipalBalanceAccrualStatus
Namespace Prefix:	ucba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of the unpaid principal balance unpaid principal balance in financing receivables that are on nonaccrual status as of the balance sheet date that have been modified by troubled debt restructurings.

No definition available.

Name:	ucba_FinancingReceivableModificationsUnpaidPrincipalBalanceNonaccrualStatus
Namespace Prefix:	ucba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of financing receivables that have been modified by troubled debt restructurings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554