Other Borrowed Funds - Schedule of Other Borrowings Advances from Federal Home Loan Bank (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Weighted average interest rate	0.35%
Federal Reserve Paycheck Protection Program Liquidity Facility	$ 344,476
Federal Home Loan Bank of Atlanta [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
FHLB borrowings	$ 115,000	$ 124,800
Weighted average interest rate	0.24%	1.92%

Federal Reserve Paycheck Protection Program Liquidity Facility.

No definition available.

Name:	brbs_FederalReservePaycheckProtectionProgramLiquidityFacility
Namespace Prefix:	brbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankAxis=srt_FederalHomeLoanBankOfAtlantaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: