XML 26 R28.htm IDEA: XBRL DOCUMENT v3.3.0.814

Organization and Summary of Significant Accounting and Reporting Policies (Details)	9 Months Ended
	Sep. 30, 2015 subsidiary
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of subsidiaries	2

X

- Definition

Number of Subsidiaries

+ References

No definition available.

+ Details

Name:	ubfo_NumberofSubsidiaries
Namespace Prefix:	ubfo_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration