LOANS AND ALLOWANCE FOR LOAN LOSSES (Impaired Loans Individually Evaluated for Impairment by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Recorded Investment
Loans without a specific allowance	$ 58,094		$ 58,094		$ 45,393
Loans with a specific allowance	13,091		13,091		8,088
Total impaired loans	71,185		71,185		53,481
Unpaid Principal Balance
Loans without a specific allowance	60,808		60,808		47,320
Loans with a specific allowance	13,579		13,579		8,612
Total impaired loans	74,387		74,387		55,932
Related Allowance	657		657		503
Average Investment	71,498	$ 54,686	72,255	$ 54,774
Interest Income Recognized	473	323	1,027	690
Construction and Land Development
Recorded Investment
Loans without a specific allowance	12,234		12,234		16,035
Loans with a specific allowance	948		948		1,536
Unpaid Principal Balance
Loans without a specific allowance	12,326		12,326		16,214
Loans with a specific allowance	957		957		1,573
Related Allowance	83		83		122
Average Investment	12,572	15,111	12,458	14,939
Interest Income Recognized	68	119	145	235
Commercial Real Estate - Owner Occupied
Recorded Investment
Loans without a specific allowance	10,318		10,318		5,427
Loans with a specific allowance	2,805		2,805		1,161
Unpaid Principal Balance
Loans without a specific allowance	10,571		10,571		5,527
Loans with a specific allowance	2,808		2,808		1,161
Related Allowance	59		59		94
Average Investment	13,130	6,471	13,262	6,507
Interest Income Recognized	116	61	238	122
Commercial Real Estate - Non-Owner Occupied
Recorded Investment
Loans without a specific allowance	7,104		7,104		6,017
Loans with a specific allowance	78		78		0
Unpaid Principal Balance
Loans without a specific allowance	7,382		7,382		6,103
Loans with a specific allowance	78		78		0
Related Allowance	1		1		0
Average Investment	7,187	9,675	7,496	9,698
Interest Income Recognized	48	48	109	139
Commercial & Industrial
Recorded Investment
Loans without a specific allowance	4,613		4,613		1,681
Loans with a specific allowance	905		905		1,295
Unpaid Principal Balance
Loans without a specific allowance	5,144		5,144		1,933
Loans with a specific allowance	907		907		1,319
Related Allowance	41		41		128
Average Investment	5,792	6,942	5,970	7,212
Interest Income Recognized	57	41	130	72
Residential 1-4 Family - Commercial
Recorded Investment
Loans without a specific allowance	6,548		6,548		4,098
Loans with a specific allowance	1,033		1,033		1,062
Unpaid Principal Balance
Loans without a specific allowance	7,376		7,376		4,879
Loans with a specific allowance	1,036		1,036		1,068
Related Allowance	131		131		35
Average Investment	7,744	4,539	7,839	4,570
Interest Income Recognized	72	30	140	66
Residential 1-4 Family - Mortgage
Recorded Investment
Loans without a specific allowance	13,783		13,783		9,512
Loans with a specific allowance	4,813		4,813		1,953
Unpaid Principal Balance
Loans without a specific allowance	14,222		14,222		9,786
Loans with a specific allowance	4,929		4,929		2,070
Related Allowance	333		333		36
Average Investment	18,876	8,772	18,951	8,802
Interest Income Recognized	63	13	163	42
Auto
Recorded Investment
Loans with a specific allowance	881		881		413
Unpaid Principal Balance
Loans with a specific allowance	1,081		1,081		577
Related Allowance	3		3		2
Average Investment	1,002	347	1,056	368
Interest Income Recognized	6	2	17	2
HELOC
Recorded Investment
Loans without a specific allowance	2,922		2,922		2,056
Loans with a specific allowance	1,459		1,459		464
Unpaid Principal Balance
Loans without a specific allowance	3,040		3,040		2,144
Loans with a specific allowance	1,469		1,469		535
Related Allowance	5		5		51
Average Investment	4,439	2,265	4,447	2,273
Interest Income Recognized	34	1	69	5
Consumer and all other
Recorded Investment
Loans without a specific allowance	572		572		567
Loans with a specific allowance	169		169		204
Unpaid Principal Balance
Loans without a specific allowance	747		747		734
Loans with a specific allowance	314		314		309
Related Allowance	1		1		$ 35
Average Investment	756	564	776	405
Interest Income Recognized	$ 9	$ 8	$ 16	$ 7

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ubsh_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ubsh_CommercialRealEstateNonOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ubsh_CommercialAndIndustrialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_AutomobileLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ubsh_OtherConsumerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: