XML 109 R93.htm IDEA: XBRL DOCUMENT v3.3.1.900

Guarantees, Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Credit losses associated with derivative contracts	$ 0	$ 0
Outstanding commitments to purchase securities	0	0
Outstanding commitments to sell securities	$ 0	$ 0

X

- References

No definition available.

+ Details

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

X

- Definition

Credit losses associated with derivative contracts.

+ References

No definition available.

+ Details

Name:	usbi_CreditLossesAssociatedWithDerivativeContracts
Namespace Prefix:	usbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Securities committed to purchase amount.

+ References

No definition available.

+ Details

Name:	usbi_SecuritiesCommittedToPurchaseAmount
Namespace Prefix:	usbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Securities committed to sell amount.

+ References

No definition available.

+ Details

Name:	usbi_SecuritiesCommittedToSellAmount
Namespace Prefix:	usbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant