Annual report pursuant to Section 13 and 15(d)

SECURITIES (Narrative) (Details)

v2.4.1.9
SECURITIES (Narrative) (Details) (USD $)
3 Months Ended 12 Months Ended
Jun. 30, 2014
Sep. 30, 2011
Dec. 31, 2014
item
Dec. 31, 2013
item
SECURITIES [Abstract]        
Federal Home Loan Bank requires Bank to maintain percentage of stock equal to outstanding borrowings     4.50%ubsh_FederalHomeLoanBankRequiresBankToMaintainPercentageOfStockEqualToOutstandingBorrowings  
Percentage of Federal Reserve Bank of Richmond reserve     6.00%ubsh_RequiredPercentageOfCommonStockInvestmentPercentageToOutstandingCapital  
Restricted equity securities consist of Federal Reserve Bank stock     $ 23,800,000us-gaap_FederalReserveBankStock $ 6,700,000us-gaap_FederalReserveBankStock
Federal Home Loan Bank Stock     31,000,000us-gaap_FederalHomeLoanBankStock 19,300,000us-gaap_FederalHomeLoanBankStock
Securities in a continuous loss position, more than 12 months, unrealized losses     1,134,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses 1,437,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses
Individual securities that had been in a continuous loss position for more than 12 months, amount     96,404,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue 34,860,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Individual securities that had been in a continuous loss position     60us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1 23us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
Securities pledged to secure public deposits, repurchase agreements and other purposes     397,000,000us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged 188,200,000us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged
Credit-related OTTI   400,000us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities 0us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsAvailableforsaleSecurities  
OTTI recovery amount $ 400,000ubsh_OtherThanTemporaryImpairmentRecovery