Capital Conservation Buffer To Risk Weighted Assets Required Under Regulatory

No definition available.

Name:	bayk_CapitalConservationBufferToRiskWeightedAssetsRequiredUnderRegulatory
Namespace Prefix:	bayk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

New Capital Conservation Buffer Requirement Phase-In Period

+ References

No definition available.

+ Details

Name:	bayk_NewCapitalConservationBufferRequirementPhaseInPeriod
Namespace Prefix:	bayk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

+ References

+ Details

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

- Definition

The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

+ Details

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

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=bayk_MortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Regulatory Capital Requirements and Restrictions - Additional Information (Detail) - Entity [Domain] - Fair Value, Measurements, Recurring - Fair Value, Inputs, Level 3 - Mortgage Servicing Rights	Jan. 01, 2019	Jan. 01, 2016	Jan. 01, 2015	Jul. 31, 2013
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio			6.00%	4.00%
Total Risk Based Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio			8.00%
Leverage Ratio (Total Assets), Minimum Capital Requirement Ratio			4.00%
Initial Capital Requirement Phase-In Period			4 years
Common Stock
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio			4.50%
Scenario, Forecast
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio	8.50%
Total Risk Based Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio	10.50%
Leverage Ratio (Total Assets), Minimum Capital Requirement Ratio	4.00%
New Capital Conservation Buffer Requirement (to Risk Weighted Assets), Ratio	2.50%	0.625%
Scenario, Forecast \| Common Stock
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement Ratio	7.00%